Water Damage but partially survived

Accidently got my phone wet while in an odder box. but the phone would still respond when pressing the home button and the button on the top. The screen however didnt respond to touch, but would light up and ask to be unlocked. sometimes it would respond and ask for my code to unlock it. I would attempt the buttons but it would lag and tell me i entered the wrong code and would vibrate. THe phone also had trouble getting a signal and continued to display "Searching" or "No Survice" instead of bars. i later tried shutting down the phone and the screen let me slide to power off.

After turning it back on the screen began to respond to touch as normal. The battery was very low though, so i plugged a usb wall charger into it. instead of charging it the battery was drained. the back also got very hot after maybe 2 minutes or so of it being plugged in and took around 30min to cool down after being unplugged. I have a little experience with iphones as this peticular one is my second, and ive been inside my first trying to fix but failing because it was to far gone. at first i thought that it might be the battery or the charging dock. but with it having gotten wet and how hot it got afterwords i hope i didnt fry anything else like the motherboard.

I dared it again to try and plug it into the usb wall charger again after the battery died and the apple symbol did come up. after a short period it went to the lock screen, but said that activation was required and that it wanted to be plugged into itunes. I tried to plug it into my computer but nothing at all happened. plugging it back into the wall the apple symbol reappeared but didnt continue to the lock screen. in my past experience this was similar to a damaged motherboard ( i hope its not but may end up being).

I plan on bringing it to a couple iphone tech tomorrow to see what kind of rundown they can give me. I would like to see what kind of diagnostic you could maybe give me because of my previous phone experiance i would very much love to make this a DIY project if it is still fixable, unless it just took this long for it to die after getting wet.

Thank you for your time, looking forward to a responce