My husband's continued for a few weeks after the treatment ended. Sorry it is being difficult for you, but it certainly sounds like it is doing something. Bests wishes on the itches!
Maria

CG to husband - SCC Tonsil T1N2M0 HPV+ Never Smoker
First symptoms 7/2010, DX 12/2010
TX 40 IRMT (1.8 gy) + 10 Cetuximab
PET Scans 6/2011 + 3/2012 clear, 5 year physical exam clear; chest CT's clear of cancer. On thyroid pills. Life is good.