After water damage, apps aren't working that I

If its only user installed applications, just delete one free one (such as facebook, pandora, etc...) and redownload it. That updates the rest of the apps on the iphone and should put them all back in working condition. (If that fixes only the free application that deleted and redownloaded, do the same for the rest of the applications).
Otherwise if all else fails, restore the iphone through itunes and resync the app's to it.
Im amazed that you got the phone working again though. I spilled a can of pop on mine for like 2 seconds, and it was toast so congrats :p.