Hello and welcome!

You mention having a full SFN workup, but don't mention any autoimmune workup. Your rapid onset and presentation sound like a possible AI process. You should consider asking for labs in this area. Keep in mind that many AI diseases can be positive even if the patient is sero-negative.

Do you have any other symptoms that appeared around the same time like, fatigue, joint pain, dryness, rashes (like butterfly malar rash)...or anything else unusual?

Were you ill with a virus or bacterial infection in the weeks/months prior to the onset? Did you take any antibiotics (especially Cipro or others in the flouroquinolone class) in the weeks/months prior?

Have you had an EMG/NCS...I'll assume if so, it was normal? Keep in mind that small fiber neuropathy cannot be detected in ENG/NCS, so skin biopsy is best test, if you can get someone to order it.