Hi Peg,
Sorry for the delayed reply here. I eventually found your case for March 10 and linked it to this question, so we can now switch back and forth to get the details. Normally to ask a case question, you start with Forum -> Ask a Case Question so that if nothing else, I get alerted someone was looking for help
Regarding Bennie, I think you're on the right general track, recognizing that he tends to be Liver Blood deficient, given the timing of the liver enzyme elevations in winter to early spring; the pale lavender tongue; the dry coat; and the appearance of lesions at the extremities. It gets worse in winter at the same time Wei Qi deficiency does, so Bu Zhong Yi Qi Tang was an excellent choice.
The worsening of the inflammation in response tells us there is a Heat condition, so using XFHMY next was logical. The biomedical basis of the Heat is the ramping up of an immune response by the Astragalus (considered a Heating herb) in the BZYQT. Other options, then, are to use immune modulating formulas like Xiao Chai Hu Tang or Qing Ying Tang (which likewise support peripheral circulation). Of the two, QYT is more cooling and is suited to nasty lesions and itch.
Real food diets tend to rule out the existence of Dampness in dogs, so XFHMY was only a partial fit, resulting in no improvement, so I'd look at one or both of XCHT and QYT. I find XCHT alone doesn't often work in dogs, and I have to use Si Wu Tang at the same time. Try a 2:1 blend of XCHT to SWT, which makes Chai Hu Si Wu Tang. Then use QYT at the same time if you like to get an anti-inflammatory edge. Hold off on the BZYQT
Also, I always make sure a Lactobacillus/Bifidobacterium probiotic is in use and that the diet is made up of about 15 to 30% plant material. Dogs that get this kind of problem on meat diets often are suffering from a carb fermenter die off, with the latter being important in elaborating VFAs that have an important effect on regulating the immune system. So, the probiotics and plant material should help make sure the treatment is more curative.
Hopefully this helps you out! Let us know how it goes! You're closer than you think, I think!