Demodex can be found on not only your lashes, but also the follicles on your face (nose, forehead, etc.). They thrive off eating your skin cells and skin oils near your hair follicles.
"Everyone has them on their skin," Dr. Michele Green, board-certified dermatologist, told BuzzFeed. "They’re normal. Some people will have more than others, and some people can contract rosacea from them."