Hi,
From what you’re saying it appears that the screen has been damaged.
The screen cannot be repaired, it has to be replaced.
Post some close up images of the screen to show the damage just to verify if this is the case.
Here’s how to do this on ifixit [guide|21499]
You will need to find the part number for the screen to make it easier to find the correct replacement part for your model.
Disconnect the power from the TV and then remove the back cover from the TV and then look for the part number which should be printed somewhere on the back of the screen panel itself.
Once you have the part number, search online using the part number ''only'' to find suppliers.
Do not be surprised if you cannot find any or if you do that the cost of the part is nearly as much as a new TV.
If you decide to replace the TV, consider advertising the TV for sale as f''aulty screen - good for parts,'' to recoup some of the cost towards a new TV as people are always looking for replacement boards for various makes and models of TVs. Just a thought