Does Myelin Sheath damage always result in Guillain-Barre syndrome?

I've had severe pain, numbness, and weakness on my legs and hands. After undergoing many MRI's, CT-scans, lab work, and only recently an EMG my neurologist says I have Myelin sheath damage, but no nerve damage which is good, of course. We don't have a course of action yet as he needs to study all the results. However, I was wondering if sheath damage always results in GBS or does GBS cause the sheath damage? By the way the neurologist has not mentioned GBS, this is something I seem to come across when I google Myelin sheath. If anyone has had experience with this I would truly appreciate your input. I'm not asking for a diagnosis as I have my doctor for that. But I would like to know your personal experience or knowledge. Thanks!