Benzoyl Peroxide 5%. Rub it in lightly(very lightly) and let it sit for a minute before cleaning it off. Use a moisturizer on it too. It could be an allergic reaction to the collar of something you have?
1. Wash it only twice a day, morning and night. Any more irritates the skin and takes away oils it needs to recover.
2. Use a Benzoyl Peroxide 5% product 1-2 times a day.
3. Moisturize immediately after using the cleanser.
4. Don't touch it, don't pick at it, and for gods sake don't scratch it. This is where self-discipline comes in.
5. Take zinc & magnesium supplements. Only 50mg of zinc a day. The magnesium is needed to absorb/synthesize the zinc to make it useable by your body. Zinc essentially helps your body control the production of 'sebum', which when overproduced causes acne.
It's that easy. Try it for 2 weeks. Acne can take acouple weeks to form, so you might not see results for that long.
Hope I could help.