They help when viruses are droplet spread and you need a lot of viral load to get sick. Only need 1 dry virion to get measles.
This is not measles. Not even close.

CDC says you need 700,000 PFU to get a macaque sick. In same category as flu. (SARS-1 was only 240). https://www.dhs.gov/sites/default/fi...2020_04_14.pdf

If the mask cuts what you emit or breathe by a factor of 5-10, it just changed the severity of your case, if you even get sick at all.