Hi Mark
The single best thing I've found for halting the growth of and shrinking fat-based tumors is a real food diet. Basically a meat- and vegetable-based diet, with minimal added carbs.
If that is already being done, then some details on pulses, their response to stimulation of different acupuncture points (if you do that), the locations of the original mass and these new masses, and the past history of the dog would help.
Tumors arising or becoming aggravated in the spring months are often Shao Yang mediated, so adding Minor Bupleurum is an idea, especially if the pulse feels quite strong. If the pulse feels weak and feeble, then consider Modified Xue Fu Zhu Yu Tang I guess
Hopefully those ideas help
Steve