Will Falconer, DVM Moderator
Hi jch,
This is the start of VAS (vaccine associated sarcoma), with all likelihood. It's beyond vaccinosis to inflammatory and probably soon out of control growth.
Also beyond DIY protocols. You need to get a homeopathic vet on board. Though, in all honesty, the handful I've treated haven't gone away and were eventually the cause of the dog's demise. I think my homeopathic vet colleagues have had similar experiences.
See my Resources link, at the very top of the page, to find the AVH list and a good homeopathic vet to help minimize the damage and slow this.
Surgery is a frustration, as it always grows back, and usually faster each time.
All the best to you. Difficult situation your dog is in, I'm afraid.