Hello, I understand your concern. Meth is a stimulant and, as such, it raises the body s core temperature. As a consequence, he blood flow to the skin is increased and sweating starts in order to lower the temperature. Due to increased sweating, the protective oily skin barrier is lost leading to dehydration of the skin which causes the itching. On top of that, the effects of meth make the dry skin feel worse, giving the sensation of crawling under the skin. All this leads to intense itching and a rash formation due to constant scratching, which can lead to skin break and irritation and become open to all kinds of bacteria, leading to infections. You can take Benadryl to stop the itching sensation, or a hydrocortisone cream which should work just as well. If there is any skin breakage or sign of infection, an antibiotic lotion (beside the Benadryl or hydrocortisone) cream would be the sensible thing to do. Ice packs on the itchy areas do seem to help. Also improving skin hygiene is mandatory to prevent infections, but avoid using harsh soaps which deprive your skin of the protective oil barrier. Ultimately, not going back to meth use, is the best long term therapy. Wishing you good health and all the best.