NonaChris

IMO, The best way to take care of your neck during radiation is NOT to have concurrent Erbitux chemotherapy. And you are doing that. (aside: this is not some personal foible, there are serious questions about Erbitux not working on 33% or more of patients and just increasing the radiation dermatitis- Dr. Gillison is checking this out as well as my CCC - although I know it to be true for me)
My RO swore by Burt's Bee Balm for his patients. My wife cannot stand the smell of it now as it reminds her of our worst times.
Whatever you use, monitor your skin. there is also a prescription gel I used: Saf Gel, a "hydrating deremal wound dressing with aglinate" although I see from Dr. Google that is now availble on Amazon (use the OCF link) and Walmart without a prescription. It was quite good and soothing.
Best wishes
Charm