Rest, anti-inflammatory medication (not vioxx)–aspirin and tylenol, liniments (Bioflexx or icyhot), nighttime padded splints for a while, swimming and water exercises, tai chi, and get rid of every drop of tension in your playing. Play as softly as you can until you can increase the tone without increasing the tension or effort. When you have a good ring in the string this is possible. If you can afford it, get Trager massage, or other massage constantly. Physical therapy is of limited help, but sometimes useful. Some chiropractics can help. Acupuncture may help.