If he starts something again then give him a good punch, might scare him because he don't think you'll fight back. Best bet is to just go to the police and see what they have to say, but then don't go and hit him or anything if they don't do anything because then he can file a complaint and get off while you get done. Just turn leave it and get on with your life (N)
Also, don't risk your education over some wanker because you'll regret it in the long run