The range of trigeminal neuralgia attacks is usually located in the sensory area of the trigeminal nerve root, broadly covering both sides of the patient's nostrils and around the corners of the mouth. The nature of the pain is quite severe, often described as knife-like pain or burning pain. The duration of each pain episode varies, often starting and stopping suddenly. Around the pain area, fixed trigger points are likely to form. Accidentally touching these trigger points while brushing teeth, washing faces, or rinsing mouths can often trigger an attack of trigeminal neuralgia. Over time, due to repeatedly triggering the pain by touching these points, patients may become afraid to wash their faces or brush their teeth, and may experience facial muscle numbness or atrophy.