What is the rash like?
Any swelling, color changes of the skin?
Skin sensitivity?? - temperature changes, breezes, touch?

If so you might want to read about RSD also called CRPS - we have a forum here - http://neurotalk.psychcentral.com/forum21.html

any thing can set if off like a minor injury, surgery, or sometimes nothing.
Some of the RSDers have FM also.

If you have a work comp claim for your work related injury we have a forum for that too.
http://neurotalk.psychcentral.com/forum30.html