Alex Ottoboni

There is a way to reset the phone in the settings menu, but with the display being black that would be impossible to get to. I would first try restarting the phone by removing the battery, reinserting it and then holding the power button down. If that does not fix it, there might be something wrong with the display or the display back-lighting. In that case the only option would be to replace the screen. Luckily, you may still be under warranty since the phone is designed to be water resistant. You could probably have Samsung fix it for free.