Where do demodex mites come from? Why do I have them?

I have demodex mites and suffer from Acne for the past 12 years. But it has gotten worse, and now I am losing hair because of them. I just need to know where the hell I got these mites from so I can avoid there primary cause? I don't own any pets! And what is the most well known effective treatment for killing and preventing them? (The only time I have not had Acne was when I used dermadoctor glycolic acid products.) Does Glycolic acid kill them? What should I put in my shampoos to stop my hair from falling out? Tweet