Why do i have so much acne, and how to i get rid of it? please help!?

well, ima 17 year old boy. i struggle alot with my acne, i started noticeing my acne/pimples around age 14-15. i hit puberty about that time. i never really cared about my acne because i always thought it would go away in couple months. im 17 1/2 and my face is worst now then it was when i was going threw that. i wash my face everyday atleast 1 time a day sometimes twice. i have a couple ideas why i got so many pimples and acne . because i have alot of stress, and i notice since i has sleeping issues when i dont sleep enough my face gets worse. i mostly got small bumps on my face ; few pimples. and its badly red marked. i used to pinch them but i stoped a while ago. can someone help tell me why i still got acne and how to get rid of it! i tryed almost every acne medication. from guys oxy cream and the pads. to girl acne meds and it still dont help. my doctor prescribed me 10% benzo peroxide but it dont help me neither. im wondering if i should go see a dermatologist. alot of people told me to try pro active. i am goin to buy it this weekend. but yeah sorry for the big paragraph but SOMEONE PLEASE TELL ME WHY I STILL GOT THIS MUCH ACNE/PIMPLES/REDNESS AT AGE 17. AND HOW THE HELL DO I GET THIS OFF MY FACE.!!!