The complication rates of carotid artery stenting (CAS) vary from 3.0% to 4.4%, and most commonly include ischemic stroke, intracranial hemorrhage, or groin complications. We present the rare complication of a patient who underwent CAS for a symptomatic 90% left internal carotid artery stenosis and developed an expanding cervical hematoma after the procedure with imminent respiratory compromise. After intubation, an arteriogram revealed perforation of the external carotid artery trunk, proximal to the origin of the internal maxillary artery. The artery was subsequently embolized and the hematoma resolved without further intervention. We present a potential catastrophic complication and suggest potential causes and treatment options available.