I believe that the rapid forms of PN... are either viral, or infectious in some way. Autoimmune PNs will start following a vaccine, or illness as well. Some drug therapies will trigger a rapid PN...like the fluoroquinolone antibiotics. Shingles is an example of a rapid viral attack. GBS is one rapid form of neuropathy that follows vaccines and illness. There are food sources too, poorly cooked chicken can result in PN from campylobacter bacterial toxins, and some spoiled or old fish will give a burning PN too.

Some of the attack may be in the dorsal ganglia along the spine.
Healing there can be spotty. There are some papers suggesting that some people have genetic errors that prevent healing in the dorsal ganglia.

http://neurotalk.psychcentral.com/thread147771.html
this link has more information on "dorsal roots"

When PN goes all over the body, it might be an inflammatory process...there are cytokines released by cells in response to assaults, and they can go haywire. RSD which is another form of neuropathy is thought to spread this way. It seems to only attack certain people, perhaps who have a genetic propensity for it. Try some AlkaSeltzer, original formula and see if you have a reduction in symptoms. The fast acting aspirin in it works very quickly to block Cox-2 cytokines. And the bicarb will block some pain receptors for a few hours. I don't recommend aspirin every day however, as your doctor should supervise that type of use.

Also you may try epsom salt baths, as the magnesium will block the NMDA receptors that register pain. If you respond to these two easy beginning interventions, it will suggest a clue as to what is going on with you.