Welcome, I also have a (working) diagnosis of SFN and have the same issues with my feet, I am waiting for a podiatry referral as I think I may have plantar facilitis too but I am struggling to manage the foot pain. I also have the sunburn type pain in various places, my hands and arms give me a lot of pain deep aching which seems to be spreading to my legs now.
I was taking cambamazipine which gave pretty good pain relief, but I have had to stop as it is effecting my liver ( according to the info this is not common) I am gutted that I can't take it anymore as I am now in a lot of pain. I also take gabapentin, I thought this was doing nothing and tried to reduce it but the pain got worse so it clearly is helping.
I also take duloxetine but I don't think that is doing a lot.
I have a course of 3 lignocaine infusions which gave great pain relief and I am waiting to have another course of these soon.
I also have given up the gym and running and am finding it all v frustrating.