touch screen dead after water damage, how could I fix it?

I have on several occasions been able to bring a board back from liquid damage, but never an LCD or digitizer. If that is not working after liquid, you're going to need to replace the screen. I'd also recommend taking the board, battery, and charge port out of the enclosure and inspecting it for any corrosion or residue. Something is there causing the heat and once any corrosion eats through the leads or traces, the board is pretty much gone unless you or someone you know is very skilled at micro-soldering (Very expensive to repair, usually not worth it for most people and its hard to find someone who really knows what they're doing.)

I hope that helps.