What is a good and fast way to treat and prevent pimples?

okay so im 13 and i have a *lot* of pimples on my face it's so saddening and i lose self-esteem. no one else has as many pimples as i do, as far as i know. i have them everywhere; forehead, chin, nose. i really want to get rid of them! and picture day is only days away...i need to have a cure for them. i dont want to have pimples on my face anymore :(. first, what's the cause of the pimple? how do i get them? is it from lack of sleep or computer? and second, what's the fastest way to treat them? i tried the toothpaste remedy but it didnt work at all. right now i use clean&clear acne prevention face wash. it doesnt really have an effect...ive been using it for months. please help!!!