Unfortunately, I don't have any suggestions. Except for maybe to try a reset? (I think there's a keyboard combination for this???? maybe?) Or else also try pulling the battery out when the phone is already turned on (if that's not how you tried it already?).
Do you keep a screen protector on it? If so, I would think that would rule out the "wet finger" as a cause. (I've got a screen protector on mine and have frequently cleaned the screen with a slight amount of water, and never any problems.)
If you don't have a screen protector, then I still doubt the water was the cause of the problem since I'd imagine "spit wet" is a pretty small amount. I mean, sure, I figure a LOT of water could cause a problem (as it did when I got A LOT of water on my laptop computer's trackpad---but even then after drying out overnight the trackpad started working just fine again.) That said... I guess you never know for sure what has caused this unfortunate situation. Hope you are able to get it working again somehow. Best of luck!