when i was in my earlier teens, i was prescribed with this stuff called 'clyndamicin' its like a roll on moisturizer for mild acne.
It was pretty good, but dries out skin.
I wouldnt say just get a cream/moisturier for when u need it, but i usually use E45, or something similar, every night, morning, and after shower, and also use a shaving balm after i shave. That helps prevent spots or anything, not just stop them.
As someone said b4, diet is important. I used to drink coke, pepsi and fanta solidly, but now (not just because of my skin) i usually drink squash drinks like robinsons, or mineral water. This really helps, and keeps skin looking young (this s beginning to sound like a tv ad!)
Also try to cut down on sugary foods, chocolate & crisps being the main culprits. This prevents breakouts etc.
Its probably generally harder if you're a big lad, so exercise would gelp, but if not, then just follow what i said up there. I would recomend the E45, and cutting down on the fizzy drinks as much as poss.
See how that goes.
If u want any more advice feel free to pm me.
Hope this helped.