Strange Shadow Overlap on Monitor

[lomlomlom]

So, I discovered this defect in my monitor today. I haven't recently dropped it or inflicted nay damage or any kind, so I have no idea what this could be. Any ideas?

(It's on the top edge of the screen, and it when I mouse through it the cursor still appears, just darker).

 

[Atreyix]

Did it just appear there? Or did it already exist and just grow? Might be stuck pixels.

 

[lomlomlom]

Just appeared. It's strange, as when I move my cursor on top it's still visible (barely).

It really looks like something is covering it. Like there's a layer of something that between the front of the screen and the backlight. It has hard edges, which is not very well represented by the picture I took.