Screen issues- flickering and strange colors

Hey,

So I recently got this iPhone that has some strange problem with the screen, I don't know it's history but someone has opened it up before and I'm not sure if they broke something or if the problem is from the lcd because it gives horizontal lines and flickers and on some occasions the screen changes to some weird colors but stops flickering or then it simply goes black.

I'm asking here to see if anyone has seen this before and has any suggestions before I waste money on a new lcd.

I added some pictures of the screen.