Hi RMD,
I can't actually remember how long into treatment that the pain kicks in. For myself I got my family to buy an aloe vera plant. Each night after treatment I would cut a small piece of the plant and rub the gel from inside the leaf onto my neck. I would also but a small amount into my mouth and try to swallow it. Remember that radiation is like microwaves and will burn the tissue, I didn't get any burn marks on my neck and I really believe this was because of the aloe. Other things to remember take pain medication regularly and don't wait till the pain gets bad. Also if your husband gets exercises to do for his swallow make sure to do them, this might be painful but it is important. I wish him well with his treatment. Keep positive, I was stage four and after treatment I am cancer free for three years now, Take care,
Noreen