I have been struggling with small nerve fibre damage for 12 months along with extreme fatigue and other symptoms off the societies web check list. I've seen neurologists, had MRI scans seen numerous doctors and had so many standard tests. The neurologist suggested Effexor for 6 months to try to raise my pain threshold to manage the nerve damage, which I have been doing. However my sister has had similar symptoms to me and she also has normal B12 levels but she responds very well to B12 injections. Within 24 hours her symptoms can start to improve and she manages well with injections and her lifestyle. I have asked my doctor and neurologist to try a B12 injection for me and the response is, why your not anemic? Please can anyone advise I'm so frustrated with trying to get to the bottom of this and rather than treat the symptom try to find the cause?