I have a black screen but sometimes it works with max brightness

I have a note 8 phone that fell and there's a small crack with a black circle next to the edge, the phone worked fine until i started using it as a Hotspot it got too hot and the screen went black completely… but in some instances the screen works with max brightness… and when I lock the screen… it would go back to being black again… everything works fine… the touch and all…

I don't think I need a new screen? Or do I? Maybe the problem is a loose wire? Because the screen works… < whenever it wants to?