He could think your weird. He could think that you look hot. He could think that you have spinach in between your teeth or something. If he really does like you then he will not just stare at you but get to know you as well, or at least try to talk to you. Trust me: I was faced this as well last year. This guy wouldn't stop looking at me and I didn't know what to make of it and ended up crushing over him, which ended in the reject pile, of course. If he does that, just ignore him, since if he does like you he should at least make a better effort than just eye contact.