This paper describes what is the evidence that BMS is a neuropathic pain disorder, and discusses how having this condition may change the brain of the patient and possibly alter their behavior. To confirm the presence of definitive neuropathic pain, the European Federation of Neurological Sciences suggests that a positive diagnostic test be added to the medical and examination data collected. Unfortunately other than tongue biopsy for small fiber nerve atrophy, no current test is adequate. There have been three studies (from two different laboratories) that suggest that while not all patients with BMS will show small fiber atrophy of the sensory nerve in the fungiform papilla, as many as 75% will be positive on this test. Next, there are multiple animal and some human studies that suggest the brain does indeed go through degenerative and adaptive changes when chronic pain is untreated. Specifically, anxiety increases, sleep disturbance is more prominent and neuronal changes promote hyperalgesia in the periphery. While most of the data on pain induced brain change is drawn from animal studies or human pain problems such as back pain and complex regional pain, there has also been one study on burning mouth patients that provides data consistent with the idea that chronic pains causes brain hypoactivity and reduced brain density.