Best thing to do is to bring it to a repair shop asap and not turn it on because if you wait too long corrosion will start and even the screws will rust. If you do turn it on it might short out the logic board and you will have several problems with it afterwards but those you can fix as well.
Most common problems are:
1. No backlight due to shorting out the chips (requires soldering on new chips)
2. Not turning on
3. Not charging (requires soldering on new chips)
4. Screen don't work. (May have to change LCD or LCD connector
5. etc.
Basically if any of these are the problems then you will have to ask your local repair shop to see if they do soldering repairs.
Best of luck