What does it mean when a boy stares at you all the time with wet lips?

Guys show their liking towards a girl much more clearer than a girl does toward a guy, but this varies with people. If this boy talks to you a lot outside of, I'm guessing school, then there is a chance that he likes you. Guys are actually shy when it comes to expressing their emotions towards the girl he likes. So if you like him or are willing to give him a chance, then smile back at him and exchange glances from across the room, this really does make a guy feel assured that you have some interest and allows him to begin hitting on you, but only if you want him to ;D