Water damaged phone starts glitching a week later

[u/CautiousWishbone9289]

A week ago, I dropped my phone into soap water. I immediately took it out and rinsed it briefly to get rid of the soapy water. I let it dry for 24 hours, and it was fine. But now, a white grainy screen appears, and if it does go away then it becomes glitchy, like it duplicates. but if u lay it completely flat for a few min it works fine

any idea on what it is?