This case report describes a 46-year-old female with a history of multiple endocrine neoplasia type 1 syndrome status post-parathyroidectomy, thymectomy via robotic video-assisted thoracoscopic surgery, and pituitary adenoma resection presenting with parasympathetic hyperactivity and Parry-Romberg syndrome. Parry-Romberg syndrome is a rare disorder that manifests as facial hemiatrophy. Reported symptoms include cognitive dysfunction, olfactory hallucinations, and parasympathetic hyperactivity: miosis of the right eye, anhidrosis, diarrhea, urinary incontinence, bowel incontinence, and orthostatic hypotension. Previous reports have noted associations between Parry-Romberg syndrome and sympathetic hyperactivity and dysregulation. This case report focuses on an association between Parry-Romberg syndrome and unopposed parasympathetic activity.