Hi Pirate - Louie here.
I've had a lump on my neck for a while. The white coats said it was just a fatty lump and didn't need any treatment. Then it started to grow as big as a billiard ball and knowing what happened to you my humans got really scared and took me to the clinic. They stuck a syringe in it and pulled a whole lot of clear liquid out, it turned out to be just a cyst so I feel a lot better now. I often think of you when my back-end forgets how to get up or I trip over my feet. Glad to hear your lump has mostly gone same as my cyst at least for the time being.
Hang in there - we oldies have to stick together.