Very poor signal after getting my iPhone 4 wet

Hello. After taking my iPhone to a festival it got pretty wet. I was almost sure it had had it, however when i got home and charged it, to my surprise it works! However, it thought there were headphones attached when there wasn't, the WiFi signal was almost none existent and the cellular signal was just as bad.

After taking the back cover off and running a hairdryer inside for a bit, i managed to fix all of the problems but the cellular signal. Could there still be moister or corrosion somewhere causing this, or is the antenna (or whatever) beyond repair now?

Really i'm just looking for advice as to what to do next. I'm more than capable of replacing internal parts, and if soldering is required i have no problems with that. Even stupidly small surface mount stuff.

Any advice is much appreciated!

Cheers,

Chris