Why haven't you visited a dermatologist? Skin care needs to be planned. And that can happen only after your skin in thoroughly examined. A customised treatment will help you and the doctor will advise you on the things to do so that you don't get acne. Till you visit a dermatologist you could : sleep early, wake up early, eat on time(NO junk food) and exercise. It doesn't matter if you are fat or thin.. You have to be fit. This helps regulates insulin levels and this keeps the acne in control.