Phantom sweating is a sensation in which the patient feels that sweat is about to burst out of skin pores, but in which sweating never actually occurs. In a series of 100 patients undergoing bilateral upper dorsal sympathectomy for palmar hyperihidrosis, 82 patients were specifically questioned and 48 (59%) reported phantom sweating. Phantom sweating started soon after the operation, was triggered by the same stimuli that caused hyperhidrosis preoperatively, lasted for a few seconds, and tended to diminish with time. In an average follow-up of 18 months, the phenomenon disappeared in 11 patients (23%). Phantom sweating is probably a symptom of residual sympathetic activity.
http://www.ncbi.nlm.nih.gov/pubmed/911065
Angiology. 1977 Nov;28(11):799-802.