White screen after iPhone in water

javier, the number one thing to remember is that Rice is a great immediate assist, but not a cure. I would suggest that you clean your iPod properly to avoid corrosion failure later on. Use this guide to clean it. The guide was written for a 3G but all of it applies to your phone as well. After you cleaned it properly, I also suggest that you change the battery. I know that your phone works, but all this can stop once corrosion sets in. It will be a lot harder to fix then. Once cleaned reevaluate for any damage. Hope this helps, good luck.