How do you know if scabies is gone? What's the difference between permethrin itching and scabies itching? Does permethrin cause night itching? Help!

Difficult. After Permethrin kills the scabies mite it will sometimes take one to two months for the itching to go away.
How long since treat. Itching with scabies is largely due to allergy against the mites. After killing the mites with Permethrin you are still allergic to the dead mites embedded in your skin. It is often several weeks before itch is gone. All contacts must be treated. See a dermatologist for treatment. There may be something else, or you may need another permethrin.