Is this white spot of light on a graphic display dangerous?

Question

Monitors

Hello. I bought a HUION GT-191 pen display on Aliexpress (for drawing). Everything is OK, it came whole, but at the same time there are defects on the display itself from somewhere. A spot of light that shines from somewhere under the matrix, with light colors, especially on white, you can see better, on black it is almost invisible and there is one broken pixel.
Can a dead pixel affect neighboring ones? And what is this stain and how dangerous is it, can the display fail? Both a pixel and a spot do not particularly interfere, and if you do not pay attention, then they are not noticeable, they do not interfere with work. You can’t just change it, I don’t know if it’s worth setting up for a replacement or if it’s not serious. Please help, I've been nervous for a week

spoiler

Video where I filmed defects, the quality is poor https://drive.google.com/open?id=1JloE-KloFVzEtdbY...

Answer 1

Is the dark spot a dirty backlight diffuser?
Bright spot - I had this when I used a screw that was too long when assembling a laptop and it rested on the display matrix at the back.
I'm guessing an assembly defect.
A broken pixel does not affect neighboring ones.