I used to fix these as a hobby and sell them on. If you didnt try to turn it on when you retrieved it, you can open up the back, take the battery out and dry it on a cloth over a warm radiator. After a day or so, take a dry tooth brush and scrub the board lightly, taking way and dried in residue and hoover it off the board. Then try switching it back on. Should work. I even done this for painter and decorator who dropped it in paint.
You can also buy packs of ebay that pretty much evaporate the water out of the phone. Always worth a try.