Go to a dermatologist for diagnosis and treatment. For me, though, I had acne into adulthood and discovered that drinking that glass of OJ every morning did it- I have a sensitivity to oranges, it appears. I can drink one glass or eat one orange a week, but anymore breaks me out, and my son found the same thing. So it could be something in your diet.
I totally understand where you are coming from!! And I know how frustrating it is and how it can really hurt your self esteem. I had horrible acne when I was 13 years old. PM me and I will share with you what has worked for me for years!!