Budl radiation effects are cumulative, like exposure to the sun. The first hits you won't notice at all, maybe not for the first couple of weeks.

Keep ahead of it before it becomes a problem. Don't wait until your skin is blistering and peeling, you should have a good moisturiser on it several times a day, but never less than an hour before treatment (it acts like cooking oil).

Oral hygiene is very important, salt/bicarb mouthwashes several times a day. None of this should be new to you, but there is a tendency to wait until you have a problem before doing anything about it. Gargling and using moisturiser in the early days seems silly when there is no pain and no noticeable effects. Keeping ahead of the symptoms will make your recovery much easier and shorter.

Report any changes in symptoms to the medics during and after your treatment. Every journey is a little different and they've seen it all. They are very experienced in what works and what doesn't, so ask them for recommendations on moisturisers, mouth washes etc.

Keep on top of your intake, as your appetite starts to drop off make sure you are getting in your calories and fluids. When things start to change, like appetite, sleeping, toileting, talk to the medics. Pain management, mental health, all challenges which may new to you can all be made easier by getting ahead of them early.

I know you had surgery, but you can be glad about one thing, at least you escaped chemo!

Some people breeze through radiation with not many effects, I hope you're one of those. Best of luck and let us know how you get on.