@carlosra that is the problem with Rice. It does not work. Never use it for any water damaged device. It does not work and all it does, it gives you a false sense of doing something good. Rice is useless as a tool
It maybe possible to get your phone back to working condition, but remember that eventually it will fail. Water damage is the hardest to diagnose and the hardest to repair since any part may have failed.
The very first thing you want to do is to not try to restart the phone. This may further damage your phone. you also do not want to try to charge it any further. The next thing to do is to clean it. Disassemble your phone using these guides Once it is disassembled, you do need to clean it properly. You will need high grade isopropyl alcohol and a soft brush. Use this guide to see how to clean it. Even so it was written for an Apple iPhone 3G all the points are still pertinent to your phone. Do not forget that you must remove all the EMI shields for proper cleaning. While you are cleaning it, check for any broken, missing or burned looking components. When it is properly cleaned, replace the battery. All these steps are to avoid delayed failure caused by corrosion.
In your case it sounds like you do not have a backlight. This could be caused by a water damaged display or a shorted backlight circuitry on your logicboard. I'd replace the display and see if that will work. For as long as you have corrosion on the board and the board is not properly cleaned and treated there is no way to say which part needs to be replaced. Remember that in case you replace your logicboard, you are going to lose your files. They are stored on memory IC's on your logicboard.