King's growth was benign! Something called a "nevus mole," a mole that became inflamed and went crazy. It makes sense. It did stay the same size for quite some time before it started growing.
To say I am relieved is to not say nearly enough. Visions of Mickey's last weeks danced in my head. King showed no sign that the growth bothered him and his eating & behavior were normal, while the Mickster was obviously sick. But still. So happy.
King's Lyme has stabilized as well, so as soon as vet's office gets the special Lyme vaccine, he will get it.
To celebrate, I am going to bake
Ultimate Ginger Cookies. The pups can't eat them, true. But Pup Mom can, and she sure as hell needs something.
Update: Mischief managed. Or in my case, c00kies!!

I wound up with 16, just like the recipe said. Sizes are a little uneven, but I will endeavor to cope. I rolled them in Turbinado sugar rather than regular white,
used dark brown sugar instead of light (recipe did call for dark brown), and used only 2 oz of crystallized ginger instead of 6 oz because I could only find the small spice bottles of the stuff and they were kinda expensive.