Hi Mel, if it has settled down now, it does sound very much like a reaction from that vibrating machine, after all the small fibres job is to they tell you when it feels hot, cold, and feel vibrations, at least you know now that those nerves are still alive, but not being 100% perfect they could only send confused signals thats why the burning started up.
Seeing that you are looking after your blood sugars now, you have probably saved yourself from all those horrible symptoms that can come with PN and if you continue to look after your blood sugars, in time, they may heal as well, which i know from my own experience can happen.
all the best,
Brian