Whats wrong with my phone screen?

I dropped my phone on the floor from a slight height. The front glass and screen are completely intact, ie no cracks or chips. But there are light white horizontal lines throughout the screen, not very visible. After a few mins, the top right corner has started becoming dark blue.

WHat do I need to replace, the screen or the LCD or something else?

I read a lot of answers but none of the descriptions matched mine.