The reason microdermabrasion is very effective for acne scars and other type of scar is because it induces the natural healing process of the skin. Removing the damaged outer layer of the skin makes the skin appear healthier.
Microdermabrasion can help to reduce the appearance of raised scars and also sunken scars. Most times, it is more effective on raised scars because it can remove the layers of extra skin one by one with each treatment. But this skin treatment can also be used on sunken scars to reduce the appearance by making the skin around the scar even.