Black fixed lines on LG led tv.

Sep 10, 2018
Hi this is my first time posting and I'm looking for some help I just recently noticed fix solid black white and gray lines on the left side of my LG LED TV. the only thing I can think of that possibly might have happened that day which was yesterday is that I went to wipe it gently with a damp cloth as I do from time to time later on when I went to watch TV I noticed 3 fix lines on the left side of the screen. I'm hoping to try and fix this myself is there any advice I could get on what the problem could be and what to do? Thank you for your responses