Judy210,
There was a time not long ago, 2009 in my case, where a feeding tube was most always recommended. It’s not the worst thing, and can be life saving to some, like me, but these days they usually don’t reccomend one unless it’s foreseen to be needed due to surgery, weight loss, etc. They say there is better prognosis without it now.
The effects of radiation usually don’t start to be felt until the after the 2nd week or 10 days of radiation. There are other phases up until several weeks after radiation, which is sometimes the worst. Recovery can take up to two years, so this is no rush game. I don’t see any chemo, which may help in recovery.
Just try to keep the weight steady, follow recommended mouth cleaning, pain relief, post radiation neck moisturizer, and rest.
Good luck, and if you have any questions, ask here, and of course the doctors!