Cleansing your face is essential but you only need to do it twice a day; and do not scrub your face. Just dont touch your skin throughout the day; this is harder than you'd think but try and think consciously each time you rest your head on your hand whilst bored in lesson etc
You do need to keep your skin hydrated, but you need to find the right products for your skin.
Unfortunately, Acne can progress into later years but does end for some once adolescence and puberty is over with.
A great product you could try is the Aknicare range, where you can get a face wash, lotion and a cream. Has worked great for me! I hope this is of some help :)