When electronic devices get wet and fail, it's difficult to diagnose what the failed part is. Most of the time it's just easier to replace the whole device. Not saying a phone shop can't repair it, but it might cost you more than what you paid for the phone.
read these and consider them for future purchases. Got Your BlackBerry Wet? - BlackBerryFAQ Buying a BlackBerry off eBay - BlackBerryFAQ