Trigeminal neuralgia is a falls under the category of “facial pain” and is sometimes referred to as “atypical facial pain.” The excruciating pain of trigeminal neuralgia originates in the trigeminal nerve. The trigeminal nerve is the fifth cranial nerve and is composed of three branches, the opthalmic, maxillary, and mandibular. Together they allow you to feel sensations on your face and control chewing. These three branches converge at the trigeminal ganglion (or nerve root) in your head. It is commonly believed that this unbearable condition is caused when a blood vessel becomes enlarged or lengthened and compresses this nerve root. 
The unfortunate patients who suffer this condition report periodic sharp, stabbing pain usually on one side of the face. It is relatively rare for Trigeminal Neuralgia to occur on both sides of the face and even rarer still for it to occur on both sides simultaneously. Patients have described pain in the eyes, ears, lips, nose, and basically all areas of the face and scalp. Pain attacks can last from seconds to hours, generally with periods of remission in between. Patients are usually pain free between attacks, although some long-time sufferers report a dull-background throb at all times.