my brother had the same problem but it went into the sea.. he had to get a replacement handset from apple for around £150 uk pounds, this is for the 32GB model factory unlocked
You have a major problem! You probably have to replace the phone with another -- see your retailer.
While water problems occur with all phones, the iPhone's battery cannot be quickly removed after a water incident to preclude permanent electronic failure. Many times, removing the battery and letting the hardware "dry out" for days, then replacing the battery, works. But not with Apple's perverted notion of keeping the battery compartment inaccessible.