Have you ever owned a laptop that developed one or more white or dark spots on the screen? Not a sharp dot or pixel, but more of a fuzzy white or dark area? It’s called an LCD Mura. Also known as LCD clouding, this condition occurs due to excessive heat and physical pressure to the LCD panel.
LCD mura or clouding can manifest itself as dark or white spots, regions, or streaks. Since this sort of damage is permanent, the only fix is to replace the LCD panel on the laptop, or to just live with it. Prevention is best: Keep your laptop screen away from excessive heat or downward pressure on the top of the laptop.
Here is an illustration of what different types of muras look like: https://www.researchgate.net/figure/239762248_fig1_Figure-1-Illustration-of-line-spot-and-region-Mura.