TL;DR: Most over-the-counter acne scar products do not say which kind of scar they are treating, which is why most of them disappoint. Atrophic scars are depressions in the dermis from collagen loss. Hypertrophic scars are raised tissue from excess collagen. Hyperpigmented marks are not scars at all, they are post-inflammatory pigment. Each one needs a different approach and the only one that responds well to topicals is the third. I went through this confusion for years before sorting it out.
A reader sent me a close-up photo of her cheek. She had been using six different scar products over eighteen months and none of them had done anything. The cheek had a mix of small ice-pick depressions near the jawline, a few raised pink areas on the lower cheek, and a scatter of brown marks across the central cheek. She had been treating them all as the same problem.
They were not the same problem. They were three different problems sharing the same skin.
This is the single most common mistake I see in scar treatment. Acne does not produce one kind of mark. Depending on the type of acne, the depth of the inflammation, and the genetics of healing, you end up with depressions, raised tissue, or pigment, and very often all three at once. The treatments for each are different, and a product that works on one usually does nothing for the others.
This article is the diagnostic framework I wish I had been given when I first started buying scar serums.
The three categories, briefly
Atrophic scars are losses of tissue. The inflammation of an active acne lesion damaged the dermis enough that when the wound healed, the tissue did not fully rebuild. You are left with a depression below the surrounding skin level. The Fabbrocini classification breaks atrophic scars into three subtypes by morphology: ice-pick (narrow, deep, V-shaped), boxcar (wider, shallower, U-shaped with steep walls), and rolling (broad, gently sloped, undulating) (Fabbrocini et al., Dermatol Res Pract 2010, PMID: 20981308). Each subtype responds to different in-office treatments.
Hypertrophic scars are gains of tissue. The healing response overproduced collagen and the resulting scar sits above the surrounding skin level. The scar is firm, often pink or red, and stays within the boundaries of the original lesion. A subset of hypertrophic scars become keloids, which extend beyond the original lesion boundary. Keloids are more common in darker skin tones and in certain anatomical sites (chest, shoulders, jawline).
Hyperpigmented marks are not scars at all in the structural sense. The skin healed flat. What remains is excess melanin deposited during the inflammatory phase of the acne lesion. The Davis and Callender review of postinflammatory hyperpigmentation noted that these marks are most common in Fitzpatrick III to VI skin types but appear in all skin tones (Davis and Callender, J Clin Aesthet Dermatol 2010, PMID: 20725554). The pigment can sit in the epidermis (lighter, browner, more responsive to topicals) or the dermis (deeper, bluer or greyer, very slow to fade).
These three categories require different diagnostic features, different timelines, and different treatments. The mistake the reader was making was buying products that promised “fade acne scars” without specifying which kind. Most such products are formulated for hyperpigmentation. They do nothing for the other two categories.
How to tell them apart
The fastest test is touch and light.
Run a finger gently across the area. If you feel a depression below the surrounding skin, you have atrophic scars in that location. If you feel a raised firmness above the surrounding skin, you have hypertrophic. If you feel nothing different from the surrounding texture, the mark is hyperpigmentation.
Then look at the area in side lighting. Shine a flashlight at a low angle across the cheek. Atrophic scars cast shadows because they are depressions. Hypertrophic scars catch the light because they are raised. Hyperpigmentation does neither because it is flat. This side-lighting test is the standard clinical approach for grading atrophic scars and the Goodman global scarring grading system uses it formally (Goodman, Dermatol Surg 2006, PMID: 17117997).
A third check is color. Active or recent hypertrophic scars are pink to red because the collagen is fresh and the local vasculature is still elevated. Older hypertrophic scars can fade toward skin tone but stay raised. Hyperpigmented marks are brown to dark brown in lighter skin and brown to nearly black in darker skin, often with sharp edges. Atrophic scars do not have a characteristic color; they take on whatever is happening in the surrounding tissue.
The reader I mentioned, when she did this assessment, had: a cluster of small atrophic ice-picks near her jawline, a few hypertrophic patches on her lower cheek from the worst of her cystic phase, and broad hyperpigmentation across her central cheek from the many flat inflammatory lesions she had during her teens.
Three categories, one face, one problem to start solving in pieces.
What topicals can do for each
For atrophic scars, the honest answer is almost nothing topical produces meaningful change. The defect is in the dermis. Topicals reach the dermis poorly and even when they do, they cannot rebuild lost tissue. Tretinoin used long-term can soften the appearance of shallow rolling scars by thickening the epidermis and improving texture, but the underlying depression is unchanged. The Connolly review of acne scarring treatments listed the in-office options that actually work: microneedling, fractional non-ablative lasers, fractional ablative lasers (CO2, erbium), TCA CROSS for ice-picks, subcision for tethered rolling scars, and dermal fillers for boxcar scars (Connolly et al., J Clin Aesthet Dermatol 2017, PMID: 29104722). The combinations and costs vary by skin type and scar morphology.
For hypertrophic scars, topicals are slightly more useful but still secondary. Silicone gel sheets applied for many hours daily over months can flatten active hypertrophic scars. Topical onion extract (the active in some commercial scar gels) has weak evidence. The mainstays are intralesional steroid injections (triamcinolone), pressure therapy, and for resistant cases, intralesional 5-fluorouracil or surgical revision. Keloids are particularly hard to treat and need specialist input.
For hyperpigmentation, topicals do the heavy lifting. Tretinoin, azelaic acid, niacinamide, vitamin C, kojic acid, alpha arbutin, and tranexamic acid all have evidence at the right concentrations. The Davis and Callender review covered the protocols in detail. The most effective non-prescription stack is azelaic acid 15 to 20 percent plus a retinoid plus daily sunscreen, used consistently for twelve to twenty-four weeks. The pigment fades. The texture is unchanged because there was no texture defect to begin with.
This is the divergence that the marketing hides. A product can call itself a “scar fader” while only addressing the third category, leaving atrophic and hypertrophic scars unchanged. The buyer assumes the product failed. The product did exactly what it could do. The category was wrong.
The contrarian section: most acne marks are not scars
I want to push back on the word “scar” being applied to almost everything that remains after acne clears. Hyperpigmentation is not a scar. The skin healed flat. The mark is pigment, not structural damage, and it fades on its own over six to eighteen months in most cases even without treatment.
This matters because patients with hyperpigmentation often think they have permanent damage and seek aggressive in-office treatments (lasers, peels, microneedling) for marks that would fade on their own with sunscreen and patience. The aggressive treatments sometimes cause more hyperpigmentation than they resolve, particularly in darker skin tones where the inflammation from the procedure triggers additional pigment.
The first question to ask before any scar treatment is whether the marks have structural depth. If they are flat, they are usually hyperpigmentation, and the treatment is patience plus a topical brightener and consistent sunscreen. If they are depressed or raised, they are structural scars and a different conversation begins.
A friend with darker skin spent $4,000 on three sessions of fractional laser for what she called acne scars. Eighteen months later her hyperpigmentation was worse, not better, because the laser had triggered new pigment in the treated areas. The original marks were not structural. She had spent on a treatment for a problem she did not have.
What I have done with my own marks
I had cystic acne for about four years in my twenties. The aftermath was a mix of the three categories: maybe ten small ice-pick scars on my cheeks, two raised hypertrophic scars on my jawline, and significant hyperpigmentation across both cheeks and the chin.
For the hyperpigmentation, three years of azelaic acid 15 percent twice daily plus tretinoin 0.05 percent at night plus daily mineral sunscreen produced about 80 percent fading. The marks are still detectable up close in certain lights but they are no longer visible at conversational distance. The cost was about $300 in product over three years.
For the hypertrophic scars, two intralesional triamcinolone injections at a dermatologist office, six months apart, flattened them to near skin level. They are still slightly pink but no longer raised. Cost about $400 total.
For the ice-pick scars, I have not done anything in-office and they are still there. I have considered TCA CROSS but not committed. The cost-benefit of in-office treatment for ice-pick scars depends on how much they bother you. They bother me less than they did, because the surrounding skin has improved enough that they are no longer the most visible feature. If they ever become the most visible feature again, I will reconsider.
This is what realistic scar treatment looks like across all three categories: different treatments for different categories, some addressed with topicals and patience, some addressed in office, some left alone.
What I would tell my past self
Categorise before you treat. Do the touch test and the side-lighting test on every mark you can see. Write down which category each one is. Realise that most people have a mix and that the mix matters because the treatments are different.
For the hyperpigmentation, the topical protocol with sunscreen will get you most of the way over a year of consistent use. Do not start there with lasers. Lasers can worsen pigmentation in many skin types.
For atrophic scars, accept that topicals will do little. Either invest in in-office treatments that match the scar morphology, or accept the scars as part of your face. Do not spend on topical “scar serums” expecting structural change.
For hypertrophic scars, see a dermatologist for intralesional steroid before considering anything more aggressive. The injections are cheap, fast, and often very effective.
The waste I want to spare people is the years of buying products for the wrong category. The marketing makes this hard. The categorisation is the only way out.
Frequently asked
Do dermarollers work on acne scars? Microneedling has reasonable evidence for atrophic rolling scars and boxcar scars over multiple sessions. Home dermarollers (under 0.5 mm needles) provide weak versions of the effect and are not equivalent to in-office microneedling. For meaningful change, in-office sessions with longer needles and proper aseptic technique are the protocol.
Will my hyperpigmentation eventually fade on its own? In most cases yes, over six to eighteen months, if no new acne lesions appear and you wear sunscreen daily. Active acne in the same areas will lay down new pigment and reset the clock. The first step is acne control. The second is patience and sunscreen.
Are silicone scar sheets useful for old scars? They have evidence for active or recent hypertrophic scars but not for atrophic scars or for hypertrophic scars more than a year old. The mechanism is occlusion and hydration of the stratum corneum, which signals reduced collagen production. Older scars no longer respond because the collagen production has already settled.
What is TCA CROSS? A technique where high-concentration trichloroacetic acid (usually 70 to 100 percent) is applied with a toothpick to individual ice-pick scars, causing controlled tissue damage and triggering remodelling. Over multiple sessions the scar depth can reduce by 30 to 50 percent. It is operator-dependent and has a learning curve, so the result depends heavily on who is performing it.
Can I use tretinoin and azelaic acid together for hyperpigmentation? Yes. The standard stack is azelaic acid in the morning and tretinoin at night. Some people use azelaic acid twice daily with tretinoin on non-consecutive evenings if tretinoin irritates. The combination beats either alone.
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Sources
- Fabbrocini G, Annunziata MC, D’Arco V, De Vita V, Lodi G, Mauriello MC, Pastore F, Monfrecola G. Acne scars: pathogenesis, classification and treatment. Dermatol Res Pract 2010. PMID: 20981308.
- Goodman GJ. Postacne scarring: a qualitative global scarring grading system. Dermatol Surg 2006. PMID: 17117997.
- Connolly D, Vu HL, Mariwalla K, Saedi N. Acne Scarring-Pathogenesis, Evaluation, and Treatment Options. J Clin Aesthet Dermatol 2017. PMID: 29104722.
- Davis EC, Callender VD. Postinflammatory hyperpigmentation: a review of the epidemiology, clinical features, and treatment options in skin of color. J Clin Aesthet Dermatol 2010. PMID: 20725554.