power button wont work

i dropped my LG in the water and everything works i was using it good but instead of using the power button i tapped on the screen 2 times and it turned on but when i tried using the power button it wouldn't work now i decided to look at what was wrong and took the battery out but now it wont turn on at all not even if i tap the screen twice and it has 90% charge so its not the battery. what can it be?