... lurking in your pores right now are tiny bugs, closely related to spiders, that live off your facial oils. Usually, these bugs are harmless, but harbor too many of them and their tendency to die and decompose while they're inside you becomes a little problematic. In fact, according to National University of Ireland researcher Kevin Kavanagh, the bugs may be responsible for rosacea, a chronic skin disease estimated to effect between 5 and 20 percent of the world's population.
More reliable sources at the end of the article (university and new scientist)
I don't usually read this blog, a friend fwd me an article on jezebel and I happened to discover this particular article. So the mites would more than likely come from your pillow case?