--you've pretty much got the state of the knowledge in this area summarized. Admittedly, the knolwedge in this area (neuronopathy) is not very advanced, and much of it is speculative.

The designation on that website of the course of small-fiber neuronopathy as progressive assumes a sub-acute or insidious onset, and an ongoing autoimmune process that is not somehow arrested or burnt out. This, of course, does happen, but it's not inevitable. If one has an autoimmune reaction that is monophasic or self-limited, presumably when that process stops, there is some chance of at least some recovery. Guillain-Barre and some other acute-onset neuropathies work this way, and it's not unreasonable to think some neuronopathies would as well.

The big question here is the extent of damage, and the supporting environment for recovery (the latter is the reason so many of us take supplements). All other things being equal, it's easier to regenerate myelin sheathing than axonal fibers, and easier to regrow axonal fibers than have other cell bodies take over the functions of damaged/dead ones.

Some of us who've had acute onsets that plateaued and then receded have reported having flares--I've had some that start up over nothing, persist for days/weeks/months, then recede suddenly. (People with chronic conditions also get flares, of course--the ANA autoimmunities like lupus, Sjogren's, scleroderma, Churg-Strauss, etc. are replete with them. I have a friend with Bechet's who goes up and down like a yo-yo.) Sometimes with nerve damage it's hard to tell if these are exacerbations or attempts at healing, as these can both "feel" very similarly (healing, "waking up" nerves do produce parasthetic or allodynic sensations). Except in long-term retrospect--do the flares last longer/shorter, are they more/less severe, how does one feel months later--it's difficult to know which way one is going.