Hello! Thank you for your question. I will be assisting you today.
I'm sorry about the issue. It looks like it could be a screen hardware issue or just a software glitch. Have you tried the following:
Unplug it, then please press and hold both the Power (On / Off) button and the Home button (which is located right below the screen) together for at least 10 seconds, until the Apple logo appears, then wait a bit, then check.