Screen filter?

Noticed that my phone's screen has this filter on, the best I could compare it to would be the photo filter 'instant', but less yellow and more darker. It makes my photos look way darker, and all the backgrounds in my photos are just black. I've tried turning it on/off, but it won't change. The apple loading screen would be the original normal no filter/bright screen, then it will eventually turn darker and my start-up screen is still dark. I thought it was the true-tone/night filter, but it isn't. Would this be a sign of water damage? My phone was near the tub since I was listening to music, but it didn't feel wet at all when I went to go pick it up.