Does he like me? If before he was somewhat a jerk only caring about himself, but now seems to be showing more.... (for lack of better word) affection?

People just don't change overnight as the Human Pschye takes at least 3 weeks to accept a change and act upon it so be careful that he isn't playing games here to just to hook you and get what he wants and with boys, this is quite common but do watch his actions as they really do speak louder than any words can and don't be afraid to dump him if he is a Player. Good luck