Tretinoin
"I suffered from chin acne for about 5 years. The spots (I think hormonal) varied from the big under-your-skin ones to white heads and I would literally get a new one every few days. I'd tried loads of different treatments from the docs, including antibiotics, and even went for face peels but nothing helped long term. My brother recommended tretinon and I was dubious at first but decided to give it a try. Bought the gel online (but I think you can get it from your doctors too). First few weeks I saw a huge improvement in the amount of I was getting although my skin did peel a fair bit. I started moisturising on alternate days and two months later the difference is incredible! Had no new spots for a month and even my acne scars are fading!"