I feel so much better.

I'm almost certain it's an abscess. It's quite warm and the back of it is sensitive.

My first thought was that she had cancer... and how LONG this must have been growing... how could I have missed it?

Marsha is my best friend... I can't even imagine what I would do if something happened to her.

Thank you, everyone, so much for your help. I couldn't find anything on the net. I was crying hysterically (still am!) and typing in every phrase I could think of with no results. Your fast and knowledgeable responses helped so much!

It seems to be originating from her mouth, not the little scaly spot. It's most swollen on her jawline.

Now if I can just make it until our vet opens.