Iphone screen is black but it still works?

So i dropped my phone in a cup of about an inch of water about two weeks ago (long story) and i pulled it out really quick and it stayed on for a while but then got really dim as in like dimmer then the lowest brightness on the phone but if you tilted it the right way you could still see what's on the screen. I put it in rice imediatly but it was already really hot when i did it. I just took it out and didn't think it worked but turns out i got the music to play and the touch screen works and vibration and sound and everything else works but the screen is still black. I was wondering if there was anything i could do to fix it or get it fixed or if it is still useless since the screen is black.

Insurance covered? Do a backup if it still powers up, then perhaps sell it to purchase another?