we've used premetherin washed clothes and linens in hot water and still have gotten scabies 3 times in 3 months. why?
scabies is a human parasite so some "human" in your midst could be re-exposing you. scabies mites do not live very long in clothing but they can live a long long time under your skin. even after they are successfully treated the itch can last quite a while giving a false impression of a reinfestation or non-cure. there are many skin conditions that can mimic scabies so in order to confirm the accuracy of your diagnosis you may need to see a dermatologist and have a diagnostic skin scraping. if you still have an infestation there are other (prescription) medications that kill scabies than the one you are currently using.