So, I have been diagnosed with Peripheral (Poly)neuropathy.
This is likely the cause of my painful skin flushing; aching, burning/prickly pains and serious allodynia in my feet; and we suspect it is causing inadequate sweating in my feet (and perhaps other areas), leading to compensatory hyperhidrosis affecting my head, neck, and trunk.
While I am happy to have a diagnosis that explains some of my medical signs/symptoms, I am sad that it is relatively untreatable. I have taken or am currently taking almost every medication used to treat PN. Pain management is likely in my future. With the recent governmental assault on opioids, I am not hopeful.
I have been hoping to find a reversible cause for my hyperhidrosis, but since pretty much everything else has been ruled out as a cause, and I appear to have impaired sweating in parts of my body...it is almost surely PN. :’( I am pretty upset about this.
My neurologist hasn’t been able to find evidence of a cause for my peripheral neuropathy, but there is the possibility that it was caused by fluoroquinolone antibiotics. The FDA has recently strengthened the warnings on these drugs, and suggest they only be used when safer antibiotics are not adequate. (Source)