iPhone 6 display is black

SIr recently i dropped my iphone 6 into the pool . i imediately recognized and i tried to switch off my phone but i failed the water enter into the display and entire scrren goes out .after that i dried my phone . after that i turned on my phone the display is black and phone turns on.. i heard the sound when i plugged into the charger. i thought display has been damaged and i brought a screen and tried again now again the display is black and i replaced the screen once again the same problem exists. i cannot connect to itunes because i put a passcode so it is not connecting to the computer.sorry for my poor english . thank you in advance