What would be my replacement part?

I dropped my phone in the toilet but luckily, I got it to still work by cleaning the screen with a 96% alcohol. I can now see everything clear on my screen and the touch screen works throughout the whole screen. BUT...there is a visible water mark behind the images/text of the bottom screen. It does not block the view of anything but it is a bit annoying to look at. I want to replace the part but what part is it? LCD screen? Screen digitizer?