Hi Veerle,
Some questions:
Why do you think his forelimb lameness worsened with the appointment? Did you adjust his neck at all? Or was there an opportunity to strain the joint?
In what way did his lumbars change with treatment. Did he have spasms there? What points did you use to improve him there?
If the only explanation for the worsening was neck manipulation, then it suggests nerve root irritation from impingement. That would make me reach for Chai Ge Jie Ji Tang. Kan sells it as Bupleurum and Kudzu Clearing Formula.
Did you get details about when the pain is worse or better during various times of day, first rising, continued motion, exertion, and weather changes? That may help narrow things down. For deficiency, Wind invasion, and spasm, NSAIDs provide little in the way of benefit. So it could be any of those three, as well as a persistent chiropractic issue
You mentioned he improved to where he is now with certain treatments. What did you use and what did he used to look like?
If you can advise on the above, I should be able to help you more. But otherwise, if you're sure the joint is puffy; if he was not worse from an adjustment but from strain to the joint; if he had a surprisingly weak pulse; and if there were lumbar spasms; then Yi Yi Ren Tang is an okay consideration
Steve