I would try PROMAXOL to reduce the pain and help healing to begin. PROMAXOL would be a good choice for your dog because it contains the stronger LM potencies. After improvement is seen then you can switch over to ARTHRO-IONX. In addition it is helpful to give Probiotics with each meal, Omega 3,6,9, MSM, and vitamin C daily. (We carry the first two and the other two you can get at a health food store.) I would also give a Choline/B vitamin supplement called Geri-Form if the nerves are contributing to the problem. The oligotherapeutic mineral base found in the IONX products helps the body to better utilize the other nutritional substances given for a synergistic response. Also be sure to give sufficient fresh water that is free of chlorine and fluoride. If you can gradually phase into a grain free diet that can be helpful too. The other thing that is sometimes beneficial is to have a certified veterinary chiropractor check for spinal alignment and make any corrections as necessary. This could be very important because of the sudden presentation of this.
Please let us know how you progress or if you have any other questions.