Not sure what you're saying about the critters they found. They were found in the mask.

Where would they be if there was no mask? In the lungs if they were going in, so the mask stopped them?

Or they came from inside and the mask stopped them on the way out? If so it's not the fault of the mask they were in there.

Not sure what you're saying.

They were found in the mask. Where would they be if there was no mask?