Subcision is a minor surgical procedure that treats depressed acne scars by breaking the fibrous bands pulling them down from underneath. A needle is inserted beneath the scar and moved in a fanning motion to cut these tethering strands, which releases the skin and allows it to rise closer to the surrounding surface. The wound-healing response then deposits new collagen beneath the scar, gradually filling in the depression over the following weeks.
How Subcision Works
Acne scars that look sunken or indented often aren’t just missing skin on the surface. Underneath, tough bands of scar tissue have formed and are literally anchoring the skin downward to deeper layers. These fibrous strands act like tiny ropes pulling the surface into a depression.
During subcision, a provider inserts a needle through a small entry point near the scar and sweeps it back and forth beneath the depressed area. The sharp edge of the needle cuts through those fibrous bands in the deep layers of skin. Providers sometimes describe hearing a snapping sound as the strands are severed. Once the tethering is released, blood pools in the space beneath the scar, forming a pocket that eventually triggers the body to lay down fresh collagen. This combination of physical release and new collagen production is what lifts the scar over time.
Which Scar Types Respond Best
Subcision works best on rolling scars, the broad, wave-like depressions that give skin an uneven, undulating texture. These scars are almost always caused by fibrous tethering, which makes them an ideal target. Deeper, wider, and more noticeable rolling scars actually improve more dramatically than scars that start out small or shallow, so people with more prominent scarring often see the biggest difference.
Boxcar scars, which have sharper vertical edges and a flat base, can also respond to subcision, though results are more modest. Icepick scars, the narrow, deep puncture-like marks, show little improvement with subcision alone because their structure is too narrow and deep for the needle to meaningfully release. Those scars typically need different approaches like chemical reconstruction or punch excision.
Needle vs. Cannula Techniques
Providers use two main instruments for subcision: a sharp needle (often called a Nokor needle) or a blunt-tipped cannula. The traditional Nokor needle has a sharp cutting edge that severs fibrous bands efficiently, but it requires multiple insertion points and carries a higher risk of bruising and other side effects.
Blunt cannula subcision has gained popularity in recent years. A clinical trial comparing the two approaches found that cannula-based subcision produced greater improvement with fewer side effects and higher satisfaction from both patients and providers. The cannula enters through a single puncture rather than several, which reduces pain and lowers the chance of post-procedure scarring. Recovery time also tends to be shorter with the cannula approach. Your provider’s experience with each tool matters as much as the tool itself, but if you have the option, the cannula technique offers a somewhat gentler experience.
What Recovery Looks Like
Subcision is an in-office procedure done under local anesthesia, so you won’t feel the needle during treatment. Afterward, expect swelling and bruising in the treated area. Bruising typically peaks around day two or three and fades within seven to ten days, shifting from dark purple to a yellowish-green tone as it resolves. Swelling follows a similar timeline, settling noticeably between days six and ten.
Most people feel comfortable going out in public around day seven to ten. By the end of the second week, bruising and swelling are usually minimal. You won’t see final results right away, though. The collagen remodeling process takes weeks to months, so the treated scars continue to improve gradually after each session.
How Many Sessions You’ll Need
Most people need two to five sessions spaced four to six weeks apart. The exact number depends on scar depth and how your skin responds. Shallow rolling scars may improve significantly after two or three treatments, while deeper scars often require three to five sessions before reaching their best result. The four-to-six-week gap between treatments gives the tissue time to heal and produce new collagen before the next round of release.
Combining Subcision With Other Treatments
One limitation of subcision on its own is that the fibrous bands can sometimes reform, pulling the scar back down. To prevent this re-tethering and boost results, providers frequently combine subcision with other treatments.
Dermal fillers injected immediately after subcision fill the newly created space beneath the scar, physically preventing the tissue from reattaching while also adding volume. This approach tends to produce more immediate, visible lifting.
Platelet-rich plasma (PRP), drawn from your own blood and injected into the treated area, takes a different approach. PRP contains growth factors that stimulate collagen production, increase skin thickness, and support tissue remodeling. It won’t provide the instant volume that fillers do, but it amplifies the body’s natural healing response to subcision. Some providers also pair subcision with microneedling or laser resurfacing to address surface texture alongside the deeper structural release.
Risks and Side Effects
Bruising is the most common and expected side effect, not a complication so much as a normal part of the process. The bleeding beneath the skin is actually part of what stimulates collagen production. Beyond bruising, possible side effects include temporary swelling, tenderness, and mild pain at the treatment site.
Less common complications include small nodules or bumps that can form under the skin if blood pools unevenly. These usually resolve on their own over a few weeks. Hyperpigmentation, where the treated skin darkens temporarily, is a concern particularly for people with darker skin tones. In rare cases, subcision can cause nerve injury if performed near sensitive facial structures, though this risk is low in experienced hands. The blunt cannula technique carries a lower overall complication profile compared to sharp needle subcision, making it a safer option for many patients.