Hello my husband has a rash across his lower back going to his leg it looked like posion ivy but did not itch him now his lower back is in pain?

Rash/pain = shingles. Your brief description makes me think immediately of shingles, a painful rash. It can be treated with anti-viral medicines, but they have to be started within 48-72 hrs to make much difference. The medicine can shorten the duration of the rash and help make it less painful. One of our Healthtap doctors may be able to help him with this.