Well, I can see there are many advice you got, but still, this situation interest me, so I'll also share my view. whee
smile First of all, your stance. If the one confessed to you is just a friend for you, then remind yourself that he's only a friend. This would help you to not succumb against your stance if, let's say you feel sorry for him and kind of want to try out. NO! That would only be mean, to the boy and yourself.
arrow Second, your action. I am a shy a person, I mean completely shy. So, I kind of understand your anxiety over this. So, I suggest that you give him a note, stating anything you want to say regarding the happening. Make it informal, just like how you would talk to him before. No, wait. Don't shake your head yet. You HAVE to try SOMETHING. Even if not giving note, you must clear the situation, put a line. Then, one more thing, try to initiate conversation, just like before. Little, by little, even though awkwardness would accompany you, things would get better.
idea Third, your judgement. All I can say is that, the boy seems to like you, I don't know about love, but he does like you. Therefore, you have to respect his feelings. How? By not denying the happening. I don't accuse you, I'm just giving advice. And don't avoid him, that is... kind of cruel don't you think?
Uh, okay. I think I'm writing down too much already. Well, I guess I'll back away now. WISH YOU SUCCEED! FIGHTING! wink
p/s: PLEASE DON'T SHOOT ME! OR WHACK ME! OR BADMOUTH ME!