What do i do if the back light on my ipod nano

Turn the thing off.  Throw the thing in a zip lock bag and fill the bag up to the top with uncooked rice. Not Minute Rice or Uncle Bens.  I'm talking about the real thing asians eat every day.  Then seal the bag up and let the rice do its thing for a week by soaking up all traces of condensation and water.  Take the ipod out and see if that works.  If you got no luck, then take it to the Apple store and have them exchange the thing out for you if your under your 1 year warranty.  Don't mention anything about water or they will deny you immediately.  You just have to play ignorant or maybe dumb and dumber.