It’s a hell of a paradox: Zits certainly pop up overnight, but their shadows — dark or red scars — seem to last an eternity. In an era in which we can plump lips, erase wrinkles, brighten complexions, and fix loads of other skin concerns in a matter of days, shouldn’t we be able to diminish acne scars with a swiftness, too? It’s a question we took to New York-based dermatologist Joshua Zeichner, MD , who immediately corrected us on one major technicality.