Hi N1.
I think you should ask rheumatologist to check your blood tests again.
I think it sounded like psoriasic arthritis, Or not? With the joint pain and all that.
Sometimes antibodies do not show up. Especially when one is on medication to fight them, I guess. I am only a lay person.
So sometimes regular checking.
I have joint pain migrating from one joint to another. My Rh factor was negative 2 or 3 times when it was checked.
But I know for sure that theese condition sure causes neuropathy. and with SFN you get it hard with paresthesia etc.