How long will it take benzoyl peroxide to work?

Up to 2 months: Acne can be a very frustrating condition. Most over the counter and prescription medications don't work to clear up the spots you have. They start working from day 1 to prevent new pimples. However, it can take up to 8 weeks for pimples to form, and some under the surface of your skin may still pop up in that 8 week period. Be patient! don't stop your acne medications and you will see results.