What happened to my iPhone 4s screen? How to fix it?

My phone screen looks like this right now
There are a lot of white horizontal lines, the main menu is nearly not visible.
Can anyone help?

The broken area at the top of the screen provides a big clue.

You have dropped, squashed, hit or bent the phone with sufficient force to damage the screen connections.

From the state of it you should consider a new phone.

I think you broke your iPhone screen, just repair it.

Be more careful with the replacement.

Your screen is damaged. Either have it repaired, or buy a new phone.