If your iPod Touch went through the washing machine and all of the buttons work but not the touch screen what should you do?

There's not much you can do from here. The water must have gotten into the circuitry of the iPod and damaged the touch sensors. This may or may not be able to be fixed. Take your iPod Touch to the Genius Bar to see what they can do. If you are still under the 1-year warranty, you can another one free of charge (possibly - they may not give you one because you put it in the washing machine).