Apple Support Community:
Turn it off and leave it off.
1. Do NOT attempt to power it on, this will likely permanently damage the device.
2. Place the device in a bag with uncooked rice or silica gel packs and leave it there for at least 48 hrs, 72 hrs
is better.
3. After it has been removed from the bag, attempt to power the device on.
Note: If it powers on and works, you are extremely lucky.
4. If it will not power on or charge, go to Apple and replace it via their Out of Warranty replacement
program.