White dust under the screen

MacBook pro Retina 2013
I have something like a dust under the screen. It is not under the screen protector, but under the pixels screen. It is traveling dust - was on the corner at first, then traveled 2 cm right. Btw there are more like this little fellows around. How to avoid it? I have no more warranty.
here is the link to see it: https://youtu.be/vRFw9yydg_4

and the image: