How long does acutane take to have an effect. thankyouuu peeps :D x?

I have had acne for about 4 years now, but it is mainly just the scars that are left. i use make-up to cover it up, but often get a little mocked for wearing too much. I dont really like looking like a tart-and i cant do certain things like swimming at school for instance, because im too self conscious of my skin. I would SOO much appreciate it if i could get a little help advice on acutane-which i have only just recently heard about x thankyouu guyss :) x