I don't know if your husband is taking anything for the rash but Doxycycline is what helped me. It's an antibiotic. Tends to dry out the skin but that better than the acne.
Diagnosed 6/28/06 with SCC of the base of tongue. T1N2bM0. Modified radical neck dissection 7/19/06. 35 x Tomotherapy IMRT began 8/15/06. 8 x adjuvant Erbitux. UPDATE: 10/4/11 - Checkup on my 5 year anniversary and I am cancer free!