[Jeckel]

It probably has a short because of your water damage. This means that it wont work under the Apple Warranty because of water damage (that is, if they can see signs of such). And if you don't have the receipt, sorry, no warranty deal. The only thing you can do now is recycle it and get a new one (if the inside of the headphone jack is pink and black, then no luck even if you have proof of purchase). No proof of purchase, no warranty coverage.