Isotretinoin
Isotretinoin is a prescription only medication that has many negative side effects. It is generally only prescribed in the worst cases of acne.
B5 Vitamins work much like Isotretinoin in slowing down the overproduction of oil that causes acne. B5 Vitamins also go by many other names including B5 Supplements, Pantothentic Acid, d-Calcium Pantothenate, and the brand name Vilantae.
B5 Vitamins can be bought without a prescription and they have very little negative side effects. In fact I've found them to have many positive side effects besides curing acne. They also help with an increase in energy and clarity in my experience.