Although your birth control pill has been shown to help acne a bit, it isn't very effective. On the other hand, it doesn't make it worse either. Your breakout is a coincidence--people your age can break out for no special reason. Microdermabrasion can be moderately helpful, but wouldn't prevent acne.
Acne treatment like the regimen your doctor put you on takes weeks or months, but it doesn't have to make you worse before you get better. You need to be patient. If the Retin-A continues to make your skin flake, please let your doctor know, since there are ways around that (other creams, less frequent applications).
Take care.
Dr. Rockoff
Dr. Rockoff