My husband got a rash on his back with our first cleanse last March. He still has it. We are on round 2 of Humaworm. RG on the Ask Humaworm forum says that it is from die off - toxins. It is very itchy. He sprays hydrogen pyroxide mixed with water on his back and that helps a little. RG says it will get better.
We totally changed our diet so as not to feed the parasites. Cut out all sugar, Sugar substitutes, dairy, meat, gluten, wheat, etc.
I also wash veggies and fruit with a hydrogen pyroxide/water soak. Keep everything clean. Wash hands often.