What do I do about a black spot on my phone?

I accidentally stepped on my phone (don’t ask) and when I picked it up there was a black chunk with a few thinner green, red and blue lines going through it at the keyboard portion of the screen.There’s also a few very thin black lines going through my screen horizontally right above where the keyboard is. I Also find it weird that it’s fully responsive, like I can even type by the part where it’s black. However the one spot with the display missing is there so I can’t see what’s behind it. . Also the screen protector only cracked so there’s no damage to the glass. I’ve reset it and nothing has gone away. What should I do? And would repair be expensive?