Mattress full of mites, check this point: they always make a nest

Simply mix warm water with tea tree oil or lavender or eucalyptus essential oil, pour everything into a spray bottle and spray on the surface.

Alternatively, you can sprinkle the surface with baking soda , leave it for a couple of hours and then vacuum it.

Furthermore, it is possible to spray a solution based on hot water and lemon juice, alternatively with white vinegar, and then proceed to wash the clothes at a temperature above 60 degrees.

It is important to intervene on mites, as they have a long life, up to four months. In this meantime, they can lay dozens and dozens of eggs. Suffice it to say that a single gram of dust can contain from 100 to 1000 mites.

However, if your mattress is severely infested , you might consider replacing it with a new one that has not been exposed to the mites.