Mental nerve neuropathy (MNN) or "numb chin syndrome" is a rare neurologic symptom most often associated with malignancy. Patients typically develop paresthesia or numbness localized to the chin and lower lip and will often seek care at their local emergency department. Pain and expansion of the lower jaw may also be present. We report a case of MNN associated with a metastatic lesion in the mandible. The purpose of this article is to highlight the importance of recognizing MNN, a potentially life-threatening symptom of metastatic carcinoma, and enable clinicians to properly diagnose MNN, which may mimic other conditions that affect the mandible.