Subcision for acne scars: how it works, results

Subcision is a minor procedure for sunken acne scars that are pulled down from below. A dermatologist slides a needle or a blunt tool under the scar and moves it back and forth to cut the bands of scar tissue that hold the skin down. The American Academy of Dermatology (AAD) describes this type of scar surgery simply: "your dermatologist surgically lifts the scar from the underlying tissue. Once freed, the skin rises, which diminishes the appearance of the scar." This guide covers which scars it suits, what studies found, the side effects and the recovery. For every treatment option, see acne scar treatment.

Subcision works on the shape of the skin. Flat red or brown marks left by pimples are a color change that usually fades on its own; see dark marks after pimples for those.

How subcision works

The full name is "subcutaneous incisionless surgery," which means surgery under the skin without cutting the surface open. A 2017 review in the journal Scars, Burns and Healing describes it: "a needle being inserted subcutaneously and handled in a fanning motion in order to untether the fibrous strands within the scar, and stimulate new connective tissue formation that will help elevate the depressed surface of scars." In plain words, the tool cuts the strands under the scar, and the small injury makes the body lay down new tissue that pushes the scar up.

A 2025 review in the Journal of Cosmetic Dermatology says the technique was first described in 1995. Since then, the tools have changed:

• Sharp needles, the original method.
• Blunt cannulas, thin tubes with a rounded tip.
• Blunt blades, which the review says look like a long screwdriver with a notched end that catches the strands.
• Radiofrequency-assisted tools, which add heat to help break the strands.

The AAD says acne scar surgery "is usually performed in a medical office or outpatient treatment center. Patients are given local anesthesia to numb the area, so they don't feel pain but remain awake."

Which acne scars subcision suits

Subcision suits rolling scars best. The AAD describes rolling scars as "wide and shallow," giving the skin "a rolling or wavy appearance." The 2017 review explains that rolling scars have bands anchoring the skin to the fat below, "thus necessitating treatment at a sub-dermal level," meaning below the skin. It says "subcision has been used mainly in the treatment of rolling atrophic scars." The 2001 paper that set out the three sunken scar types, ice pick, rolling and boxcar, included subcision in its treatment plan.

Ice pick scars are narrow and deep, and the 2017 review found they responded best to a strong acid placed into each scar; see chemical peels for acne scars. Shallow boxcar scars respond to resurfacing treatments such as laser. The types of acne scars guide shows how to tell the types apart. Most people have more than one type, so a dermatologist often combines treatments.

What the studies found

The studies on subcision are small, and they measure results in different ways. Here is what they report.

• A 2005 study of 40 people with rolling scars in Dermatologic Surgery found that patients and the researchers estimated the improvement at 50 percent, and "ninety percent of treated patients reported that subcision improved their appearance." The results held at six months.
• The 2017 review found 10 studies of subcision for acne scars and reported improvement "in the range of 10-100%." In one study of 34 people with mainly rolling scars, moderate or severe scarring was present in all at the start; six months after subcision, 53 percent had only mild scarring.
• A 2024 randomized trial treated one side of the face in five people with rolling scars, using five subcision sessions four weeks apart. The other side got no treatment. Scar scores fell more on the treated side, and the authors concluded that repeated subcision "may improve the appearance of rolling acne scars compared to no treatment."
• Another 2024 randomized trial compared subcision alone with subcision followed by 10 sessions of suction on one side. Blinded dermatologists saw no difference between the sides at one or four months. Patients felt the suction side improved faster at one month (37 percent compared with 24 percent), and more of them preferred it.

The 2017 review adds a warning about rolling scars: they "have the highest rates of treatment failure," with 10 to 15 percent failing with subcision in one study. A 2016 Cochrane review, which pools trials to judge how strong the evidence is, found a lack of high-quality evidence for all acne scar treatments.

Why scars can sink again

After the strands are cut, they can form again and pull the scar back down. The 2025 review says that after needle subcision, scars often sink back, and the overall results are moderate. A 2023 review of clinical trials in the Journal of Cosmetic Dermatology says that combining subcision with a filler, such as a hyaluronic acid gel or the person's own platelet gel, "can improve outcomes and prevent the re-depressing of scars, as can its combination with frequent suctioning." The same review found that blunt cannulas and needles give comparable results, and that cannulas cause fewer side effects.

The AAD gives a similar example of combined treatment: a dermatologist "may perform acne surgery to lift some sunken scars and then inject a filler to give the treated scars more volume." See dermal fillers for acne scars. It also says "another procedure like laser resurfacing or platelet-rich plasma may be used after acne surgery to improve results."

Side effects and risks

The 2025 review lists the main complications of subcision as "pain/tenderness, bruising, infection, formation of subcutaneous lumps, and dyspigmentation," meaning skin color changes. It says most of them "resolve spontaneously postprocedure without the requirement of further interventions." The 2005 study adds that swelling, bruising and pain pass, "but patients may have persistent firm bumps at the treatment site."

Details from the 2025 review:

• Bruising. In one study of 28 people, the side treated with a sharp needle had 17 cases of bruising, compared with 8 on the side treated with a blunt blade.
• Infection. Uncommon. In a trial of 100 people, four infections occurred in the needle group and none in the cannula group.
• Blood collecting under the skin (hematoma). Rare; the review lists steps doctors take to lower the risk, including checking medicines that affect bleeding.
• Numbness. Cutting small nerves can cause numbness, most often on the forehead. It usually improves "within 6-18 months," but "permanence has been described."
• Dark patches and entry scars. The spot where the tool enters can darken or form a small raised scar. Fewer entry points and strict sun protection lower the risk.

The review concludes that "subcision is a safe treatment for acne scarring," and that complications occur more with sharp instruments.

Who may need to wait

The 2025 review gives doctors several cautions before subcision. It advises avoiding subcision where the skin has an active infection. It suggests medicine to prevent cold sores for people who have had them before. It also asks doctors to check each patient's bleeding risk, including medical conditions, medicines that thin the blood, and blood pressure control. If you have active acne with painful or pus-filled spots in the area, tell your dermatologist, since the AAD says scar treatment usually starts once acne is under control.

Recovery and aftercare

Expect swelling, bruising and tenderness in the days after treatment. The AAD's acne scar aftercare advice applies:

• Follow your dermatologist's instructions for washing and caring for the treated skin.
• Apply broad-spectrum, water-resistant sunscreen with SPF 30 or higher every day, and limit time outdoors for 6 to 8 weeks.
• Expect results to take time, because the body needs time to make collagen and elastin.
• Return for every planned session. The AAD says acne scar treatment rarely takes a single session.
• Keep treating acne. "New acne breakouts could cause new acne scars."

Before you book

Tell the dermatologist about every acne treatment you have used in the last two years, as the AAD asks, and about any medicine that affects bleeding. Ask which tool they use, how many sessions you may need, and whether they plan to add a filler, laser or other treatment. The AAD says medical insurance does not cover acne scar treatment, and this guide found no independent medical source that lists subcision prices, so ask for the total cost.

When to see a dermatologist

See a dermatologist if you have wide, wavy dents that bother you and your acne is under control. Skinli gives general education and is not a doctor, and it cannot tell scar types from a photo. The free Skinli acne plan can help clear the acne that comes first.