Welcome @sunflowergirl050710, It's difficult not to worry about a treatment when you are not sure of possible side effects. I don't have any medical training but from what I've read I'm not sure it would be the underlying cause of small fiber neuropathy. Here's some information from a clinical trial on the topic.

"The antibodies to TS-HDS and FGFR-3 are detected in up to 20% of patients with otherwise idiopathic small fiber neuropathy, but are rare in patients without small fiber neuropathy."
--- IVIg for Small Fiber Neuropathy With Autoantibodies TS-HDS and FGFR3:
https://clinicaltrials.gov/ct2/show/NCT03401073.
There are a couple of discussions that might be helpful for learning what others have shared about IVIG infusions:
--- IVIG Infusions: https://connect.mayoclinic.org/discussion/ivig-infusions/
--- Chronic Inflammatory Demyelinating Polyneuropathy and IVIG reactions: https://connect.mayoclinic.org/discussion/cidp-having-ivig-reactions/.

Do you mind sharing what kind of neuropathy symptoms you have or other treatments you have tried?

Hi- I was wondering if you ever went forward with IVIG? I was diagnosed with the FGFR3 antibody in late 2019/early 2020. By the time we got around to discussing treatment options, it was covid lockdown and the idea of going out for infusions or doing home infusions with a stranger sounded crazy.

But then my neurologist left and so far there hasn’t been a provider willing to implant her plan of care or who felt knowledgeable. I’m considering it again, but because the blood test isn’t fda approved and neither is IVIG for this purpose, my insurance may not cover it and it’s kind of a toss-up whether or not it would help. So I’ve just been sitting on it. I wanted to ask what your experience has been?