My camera is showing a green screen when it is turned on?

I had the camera in my sports bag and the bag got wet in the rain. I completely forgot about the camera when I got home and it was left in the bag overnight. The next morning I try turning the camera on but it doesn’t switch on, I then later on in the day put the battery in and it shows a green screen with a water mark on the main screen, the camera is currently in a bag of rice. What is the problem and what should I do?