Replying to Dealing with assholes

theres a dick at my school whos friends with my friends but i hate his guts, anyways he has just buggin the shit out of me at lunch today so i like took my sandwich gab and hit him with it, then he fills a cup with pop and chases after me and pours the whole thing on me, i had a detention so i had to go and he ran away so i couldnt do anything then. he is just a little shit but i gotta show him he cant bug me what should i do, should i figth him or just forget about it and finnish this last month of school graduate and never have to see him again?