I am not sure but before the rsd dx when I was dx with PN it was in one leg and then spread to the other and my neuro said that PN can spread as well. Have you had nc or emg? How did they come up with nerve damage? The treatment in rsd and pn can be similar. The thing with PN is if you can find the why behind it like if you have auto immune or diabetes you can treat that and it can really help. I would call your doctor and tell about your fears/concerns/reactions. Sometimes meds take adjusting time and sometimes it is not for you. Many thoughts