Hi babba,
You need to find a good Neuromuscular Neurologist. My SFN also started with burning feet and tingling in my lower calves. My neurologist at the time (3 yrs ago) insisted it was anxiety! I was so angry and frustrated with him because I knew it was not anxiety! (I wish it was only anxiety)! Finally after a year of tests (emg/ncs, mri's-brain, spine, bldwork, etc) and a waste of time going back and forth to my Doctor/Neurologist that thought "it was all in my head" , the Neurologist decided to do a Punch Skin Biopsy. That test is what confirmed I had SFN. The test result read: Consistent with small fiber neuropathy. Nothing else, no swelling, or other "problems". Mine is Idiopathic, 3 yrs later , still no known cause!
They wont "listen"to you. You have to insist and tell your Neurologist you want a skin biopsy. Do you have symptoms of small fiber neuropathy? Have you had any tests yet? I hope this helps...