it wasnt bad for me. you have to drink a lot of fluids before you have it and lay as flat as possible after it for a number of hours.

a skin biopsy can tell you if you have small fiber neuropathy but wont tell you what the cause is.

a lumbar puncture is used to look for or rule out autoimmune markers, infectious disease , lyme disease, multiple sclerosis, and chronic inflammatory demyelinating peripheral neuropathy. It wont tell you whether you have small fiber neuropathy.