I just had the same thing happen to the same camera on a fishing trip in Alaska. I had the camera in the zippered pocket of my rain jacket. When I took it out to take a pic the screen had lines in it.
I viewed a few You Tube clips about changing the LCD screen yourself and decided to give it a try. I ordered the part, $28, and I'll let you all know how it comes out.
I also went and bought a Panasonic water proof camera, TS2 I think. It was on sale at Fry's for $79 .... I'll use it for wet weather and close up hunting / fishing shots, it has a 4X zoom and it takes video. I also will use it as a trail cam chip viewer and not have to worry about getting the DMC ZS3 wet again..