The electronic Textbook of Dermatology
http://telemedicine.org/stamford.htm
At the idex on the left look up 'diabetic neuropathy'....and read on. While you don't have that condition...you may find that many aspects overlap.

I will warn you that it's not exactly light reading, but, it's packed with not only skin/scalp conditions, but explanations on how our neuro conditions interact and affect other body systems.

Hope it helps - j