Hi Michael,
I like your idea of Si Miao San to start with, coupled with diet change to a real food diet. The latter may be a pain in the owner's eyes, but is critical, both to counter the possible Damp Heat underlying the lesion (given the lanolin coat, slippery pulse, and purple red tongue) but also because of the fact that it appears real food diets may increase the prognosis for tumor control using natural means significantly.
The rapid growth tells us we need to move blood away from the tumor, which SMS does. Modified Xue Fu Zhu Yu Tang would push it towards it, so I'm not thinking that is the correct way to go.
Sometimes a mixed effect of being anti-inflammatory while promoting normal circulation is needed to address tumors. If that turns out to be the case, for oral tumors, I try Qing Ying Tang. But to start with, I would use Si Miao San, as well as Hoxsey and Boneset (because of the likely bony involvement and its reputation in other Damp Heat tumors like osteosarcoma). You can find both of those easily at A Time to Heal Herbs
Let us know how it goes!
Steve