Why won't my wifi work for my iPhone 3gs?

I have had my iPhone 3gs for a little iunder a year and my wifi has never had a problem. I admit that i dropped it in water a little over a week before i had problems, but right away after i dropped it it was working so i know it can't be because of that.

I have tried everything from changing the wifi password to restarting my phone. My phone is updated and i have the correct password it just says unable to connect to the network linksys. This is very annoying and i'm worried i am going to go over my data plan, which can get expensive.

Please give me your advice. Anything will help, don't be afraid to comment. Thanks in advance 🙂

-Christine