Well, I'm quite sure that if he was doing it just for the pure release of it then he wouldprobably hide from you and everyone else. If he's parading it around or just letting it be seem anyway then he's probably after some help. But I know for sure that self-harming is going to get him no-where but down... it's a vicious circle; you feel down, you hurt yourself, you feel bad because you've hurt yourself. There is absolutely no way this guy can possibly be feeling that much better from doing this.... it's a temporary fix, like a drug y'know? That sudden rush of adrenaline and endorphins.
You could advise him to get in touch with other self-harmers on the net. It's therapy and mutual friendliness.
But you might find it hard to touch the subject with him. But just make sure that it's an absolute NO BULLS**T APPROACH! Self harmers will not respond to pussyfotting around, that's for sure. You may not be able to say muh to him but that you're always there for him but also that you won't stand to watch a friend sabotage their potential like that.
Anyway, as long as he's keeping it superfiial I think he'll 'grow out of it'. Self harmers tend to go on a maddun for a couple of years before realising that it got them nowhere.
And yes..... I've seen it all before. I'm not making this stuff up as I go along.
Good luck. Just remember... patient, understanding and empathetic but NO CRAP approach. This guy may just feed off the "there there"s and the "aww, poor you"s. He needs to see that this behaviour gets no sympathetic results.