I feel all your pain! I had demodex brevis (mange!) that lives in sebacious (oil) glands for years! I researched like a mad scientist...Diatomaceous Earth over body morn & night & after showering.(Buy at any hardware/drugstore..in pesticide section.) It literally cuts them open like shards of glass & die instantly on contact. I also use borax, and consume 1 tsp a day (to a gallon water..whatever you can handle) & it sterilizes the males that come out on your face at night to feed & mate (because of borax in your system) & has many other nutritional benefits, alkalizes water & system, aids digestion/elimination/ vitamin & mineral absorption, etc.
I also had bedbugs..when I thought I rid them from my body, (many hours of self care!) I found them nesting, living on & under my scalp! I made a paste of 1/5 borax- to 4/5 diatomaceous earth & water...put on scalp & sleep overnite w/shower cap & wash & rinse in am. The "clay" literally pulls them out of your skin (its a dessicant) I use a more watery solution of it all over my body, too. Heat from clothes dryer will kill bedbugs. Oh, I also take a tsp of food-grade diatomaceous earth every day to slough off crap from intestines, and it kills any living parasite in digestive tract. These infestations are REAL! Though I dont complain to family or anyone that matters, for the same reason of being labelled as crazy!! I hope this helps some people, it causes such pain, shame, isolation, I know. But dont tell the pharmaceutical companies that this can be solved w/a $5 bag of diatomaceous earth and a $6 box of borax!....ALSO... Any dish soap, shampoo, etc, put in spray bottle w/water, willkill instantly ANY insect on contact. No need for poisenous insecticide!! (Sorry Dupont & Monsanto!) Good luck & hang in there!