If he is getting high strength topical corticosteroids they can cause a thinning of the skin and other issues as well. If you haven't already, be sure to inform the dermatologist of the topical meds. Stress can also impact the skin (the largest organ of the body). What other variables are in play since before Tx? Maybe he's having reactions to other creams and or lotions. Possibly the creams and/or lotions have gone bad and are causing skin reactions. It's a process of elimination.
I am unaware of anyone having this severe of a reaction to
Erbitux, this long after treatment, particularly since Tx was cut short.
IMRT is typically programmed to avoid the thyroid. I had almost 70Gy of radiation and my thyroid is fine. They finally stopped giving me semiannual TSH tests.
It is odd that they would use IMRT for "carpet bombing" the "unidentifiable tumor" (aka "occult" tumor). Why wouldn't they use XRT for that since there should be an identifiable target for IMRT?