Gary S;
I'm sure it was a combination of rad/chemo but I lost all my facial hair through treatment. I didn't shave at all after about a month into treatment and even after treatment the only hair growing back was up by my ears. Now, about three months out I have my moustache back, almost as thick as it was, but my goatee is gone. I do have some whiskers starting to pop out around my chin though. Like you, my entire neck area is totally smooth. Folks staring and commenting don't have a clue to the path you have walked and that is their issue. My thought is if it grows back that's nice. If not it sure doesn't affect my breathing!

Best of Luck,

Steve