You may wish to consider Botox. Since its inception as a sure fire wrinkle suppressant, it's been found to have other neurological applications. It's now site injected to decrease sweating in both the arm pit and feet. Whether this sort of off label application would help is impossible to know but it is being used in a wide variety of pain suppressing uses. Also, have you considered acupuncture?

5 year old thread with the last reply being a year ago...