PIE is not a scar, it's wounding from acne. Think of it as a burn or scrape.
Give it a try, tretinorin it's a recommendation (works for some) along with many others in the faq - top of the sub where you posted this, click on that, and goto the PIE recommendations under skin

BA - agree with you... time and SPF+++++ then wait. May last 6- 12 months. Aim is to improve with every month.. if not.. vascular lasers such as V BEAM, KTP, 755, genesis and even IPL can help.