On this page
Start here: is it actually a scar?
A true acne scar is a permanent change in the skin’s structure — tissue was lost or over-produced during healing, so the surface is no longer flat. A dark mark left behind after a spot clears is not a scar. It is post-inflammatory hyperpigmentation or erythema: pigment or redness sitting in otherwise intact, flat skin.
Run a finger over it. If the surface is smooth and only the colour has changed, it is a mark and it will fade. If you can feel a dip or a raised ridge, it is a scar and it needs structural treatment. This single test determines which half of this article applies to you — and it is the most common mistake people make when buying products.
The four types of acne scars
Atrophic scars — where tissue was lost — account for roughly 80–90% of acne scarring and come in three shapes.
Ice pick scars
Narrow, deep and steep-sided, like a puncture made with a needle. They are usually less than 2 mm across but extend deep into the dermis, often on the cheeks.
Why they are the hardest: the depth-to-width ratio means resurfacing the surface does almost nothing. You would have to remove an enormous amount of surrounding tissue to meet the base.
What responds: focal techniques that treat the scar individually — TCA CROSS (a high-strength acid applied precisely into the scar to force it to contract and refill) or minor surgical punch excision. Broad resurfacing alone will disappoint.
Boxcar scars
Wider than ice pick scars, with sharply defined vertical walls and a flat base — like a small crater. Typically 1.5–4 mm across, on the cheeks and temples.
What responds: collagen induction into the base and walls, most often microneedling, sometimes combined with subcision for the deeper ones or fractional resurfacing to soften the sharp edges. Shallow boxcars respond well; deep ones need multiple modalities.
Rolling scars
Broad, shallow depressions with sloped, indistinct edges that give skin an undulating look. They are caused by fibrous bands tethering the skin down to deeper tissue.
Why they behave differently: the surface tissue itself is often fine. It is being pulled down from underneath.
What responds: subcision — releasing the tethering bands — is the primary approach, followed by collagen stimulation to fill the released space. Treating the surface without releasing the tether tends to give short-lived improvement.
Hypertrophic and keloid scars
The opposite problem: too much collagen was produced, so the scar sits raised above the skin. Hypertrophic scars stay within the original boundary; keloids grow beyond it. Both are more common on the chest, back and jawline, and both occur more frequently in melanin-rich skin.
What responds: corticosteroid injections, silicone therapy, pressure and specialist care. Critically, collagen-stimulating treatments are the wrong direction here — the problem is excess collagen, not a deficit. This is why identifying the type before treating is not academic.
Do acne scars go away on their own?
Marks do. Scars do not.
Post-inflammatory hyperpigmentation typically fades over three to twenty-four months depending on depth and skin tone. Post-inflammatory erythema — the pink or purple flat marks common on fairer skin — usually resolves within three to six months. Atrophic scars, once formed, are permanent without intervention. They can be significantly improved, often by 50–80% with a proper course of treatment, but “erased” is not a realistic promise from any credible provider.
What treats what: a summary
| Scar or mark type | How to identify it | Primary approach |
| Post-inflammatory hyperpigmentation | Flat, brown or grey | Pigment-focused: acids, brightening actives, strict SPF |
| Post-inflammatory erythema | Flat, pink or purple | Time, barrier support, vascular treatment |
| Ice pick | Deep, narrow, steep | Focal treatment (TCA CROSS, excision) |
| Boxcar | Crater with sharp walls | Microneedling, fractional resurfacing |
| Rolling | Broad, sloped, wavy | Subcision, then collagen induction |
| Hypertrophic / keloid | Raised above the skin | Steroid injection, silicone — never collagen stimulation |
Why collagen induction is the workhorse for atrophic scarring
Most atrophic scarring is treated with some form of controlled injury that provokes new collagen into the deficit. Microneedling is the most widely used because depth can be adjusted precisely and it does not rely on heat or acid — which makes it comparatively safe across all skin tones, including Fitzpatrick IV–VI where heat-based lasers carry higher pigment risk. How collagen induction therapy actually works covers the mechanism and the four-to-six-week session spacing that follows from it.
Expect a course, not a session. Collagen remodelling runs for months, so the honest timeline for meaningful improvement in established scarring is six to twelve months.
The part everyone underestimates: preventing the next round
Two things drive scarring — the depth of the original inflammation and how long it lasts. That leads to three unglamorous rules.
Treat active acne properly and early. Every month a nodular lesion stays inflamed increases the structural damage underneath.
Stop squeezing. Manual extraction of a deep lesion pushes inflammatory contents further into the dermis. That is exactly the mechanism that converts a spot into a scar.
Wear sunscreen daily. UV darkens existing marks and prolongs their fade. On melanin-rich skin the effect is more pronounced and longer-lasting — and there are specific reasons why.
If you are treating with peels as part of a scar plan, the aftercare window is where results are won or lost. Our day-by-day peel aftercare guide sets out what that week should look like.
Frequently asked questions
Can acne scars be removed completely? Improved substantially, yes — commonly 50–80% with a full course. Complete removal is not realistic, and anyone promising it is overselling.
What is the best treatment for acne scars overall? There isn’t one, because the four types respond to different mechanisms. A single face often needs a combination.
How long until I see improvement? First visible change around six to eight weeks after a collagen-induction session; full remodelling over three to six months. Plan in months, not weeks.
Are at-home derma rollers worth trying for scars? No. They cannot reach the depth required, cannot be adjusted per scar type, and carry infection risk. For structural scarring they are the wrong tool.
Written by Parull G Chandna, Advanced & Medical Aesthetics at Kaaya Skin & Hair Studio, London, Ontario. For an assessment of your scar type, explore our advanced skin care treatments or book a consultation.