Thanks so much! I'll look into that stuff!
It didn't seem to be the actual collar that rubbed the hair off... more the tags or the rings on the tags that rubbed it off.
Good news is, I think I saw a few "sprouts" today! Woot woot! He's got a very fine fine fiiiiine fuzz on that spot, so maybe that will grow out longer. The sprouts though, seem to be a few random longer hairs. Yay!