Good News for Loki!
The vet called me today and told me that both the existing shoulder lump and the new jaw lump are benign basal cell cysts! She said if he gets anesthetized for something, I should see if they have time, etc., to take these off, but there isn't any reason to take them off now. I need to watch them and him and if anything odd happens, I should bring him back.
I had another strange change that I forgot to post yesterday -- while I was in the bathroom on Friday, looking in the mirror closely, I saw what looked like a hair that was both silver and brown. I carefully pulled it out to see if I was right, and it was even more strange -- the brown was in the middle and the silver was at both ends!