Screen "blemish"

You say it is "on" the screen; can you feel it with your finger? Or is it really "in" the screen? As seen here, there typically are several layers to an LCD screen. Sometimes, you even hear of "noseeums" or tiny gnats getting in between the layers. Some times they will crawl back out if you power off and shine a bright light towards the closest edge. But typically is die in there, and then there is nothing you can do about them. They may shrink as they decompose and maybe inch their way to the bottom of the screen - but that typically results in the user being even further annoyed.

But if the smudge is on the outer layer, perhaps some eyeglass cleaner and gentle rubbing with a soft, microfiber cloth will clean it up.

If it is a "divot", it seems you should be able to feel it. Perhaps something was sitting on the keyboard when you closed the lid. Sadly, you can't get rid of a "dent", like you can a dent in a car door. You probably will just have to live with it.

I guess you could try an external monitor, just to make sure it is the screen and not something in the graphics "signal" being sent to the screen.

 

Then I can only assume you ducked and something hit the screen, or something got squished against it when the lid was closed. Not good.

 

Even if such a thing, I think it might be like viewing something through a glass of water, or seeing your reflection in a carnival mirror. Clear, but distorted out of shape.

But still that would only fill the divot, not pull it and level it out which is needed. Right now, you see the darkness around the divot because the light from the pixels and/or backlighting is being blocked or creating a shadow there. It seems to me a filler, regardless how pure and transparent it is would not help get rid of that shadow.

I'm doing a lot of guessing here so I could be wrong. But it seems to make logical sense - to me anyway. And so I fear your only recourse is to learn to ignore it, or replace the screen. And replacing the screen always introduces the risk of collateral damage during the replacement process - assuming you can get a correct replacement that is of equal quality (and not end up with an inferior looking, cheap, counterfeit knock-off ).