What is the most effective non-prescription acne medication?

acne medication
Helen of Troy asked:


I am a teenager and I get the normal whiteheads and the painful, long-lasting under-skin pimples as well. I have tried many types of acne medication and they have either been useless or made it worse. I have oily skin. My acne is not really severe, but it is still painful and embarrassing. What would be the best thing for me to use? Thank you so much!