FACIAL PAIN: A 21st CENTURY GUIDE For People with Trigeminal Neuralgia Neuropathic Pain TN and Other Conditions Comorbidity is the presence of more than one medical condition in a patient. Some examples include Multiple Sclerosis, brain tumours and Lyme Disease. 7.1 Multiple Sclerosis Kenneth F. Casey, MD (USA) Facial pain occurs in 2% to 6%…