Firstly, it is important to drink lots of water. dont scrub at it in the shower, and when u wash ur face, use cool water. hot water tends to upset acne(i know from personal exp.) I know people with moderate acne that have used tea tree oil with good results. get 100% solution. u can find good brands at health food stores.
I dont know how often to put it on every day, but i would imagine 2-3 times a day. too much fried, or greasy, fatty foods can also contribute to acne. Getting enough vitamins is good for your skin, especially vitiman a and e. if tea tree oil seems to help, u can buy soap with it in it that u can use to wash the acne. the oil helps by killing the bacteria that cause acne, as well as penatrating and cleaning out the pores. Just remember, for somthing really bad like youus, you have to hekp prevent it from the inside as well as the outside by eating less fried, greasy foods, geeting enough vitamins for the skin, and drinking enough PURE water, not coffee or coke