this past weekend one of my friends from home came down to my university for a weekend of partying.(we are both under 21) We both have a lot of drinks and we start ruffhousing, he gets angry and hits me and i then get angry and hit him in the face, which chips off part of his molar. there was no police report filed and he and i seemed to have made up. I woke up and he was gone the next morning very early and he will not return my phone calls or messages. I know he is the type to sue, can he sue me? if so how can i prevent or save myself?