There is, however, considerable risk of developing a post-sympathectomy pain syndrome that may be the result of a denervation supersensitivity of alpha receptors.
http://www.mc.vanderbilt.edu/.../Comple ... Syndrome-1...
Paradoxically it has been suggested that in some cases there may be abnormal vasoconstriction rather than the expected vasodilatation after sympathectomy.
ats.ctsnetjournals.org/cgi/content/full/84/3/1025