Micro-dermabrasion should not be performed on young skin unless it's in medically supervised setting.
I've seen too many young women do cosmetic micro-dermabrasion at home or through unscrupulous beauty therapists, get hooked on the temporary sensation it provides and thoroughly destroy their previously healthy skin.
Use a fine micro-polishing scrub once a week, and go to a proper skincare technician and see about your dry skin and mild scarring. They'll hook you up with the right products and give health/lifestyle tips to correct your skin in the long term, not give you a damaging quick fix.