(1) shake out all the water
(2) take out the battery (and leave the back cover off until it's dry)
(3) if it was really wet inside, you may need to disassemble it (and leave it apart until it's dry)
(4) let it dry out for a week or more
It might work after that. My neighbour's went through the wash in her jeans pocket, and survived*.
After you put the battery in, you may be able to select DOWNLOAD and get your old character back.
(* = the first time. The second time it wasn't so lucky.)