Hi, my iPhone is having a green vertical line

Hi, my iPhone is having a green vertical line all of a sudden and I don’t know how that happened. I was using the phone and it was perfectly fine, I kept it down on the table for just max 5 mins and suddenly I see this green line.

i m so so so worried. Please help me. I didn’t damage my phone or had an accident with it. Please help me.

I’m attaching a picture for the reference. Please help me..

Thank u .