Where's your friends RSD? Mine started in my left wrist but spread up my arm, shoulder into the left side of my face before going south in my chest and my left leg.
I don't get blisters but the left side of my gums are a different color and the teeth are getting brittle.
So to give you an answer I would lean towards RSD. This monster we deal with has many faces and affects everyone a little different as well as the same.
I hope this helps...