Trigeminal Neuralgia -

Trigeminal neuralgia is a chronic pain condition that affects the trigeminal nerve, which carries sensation from your face to your brain. If you have trigeminal neuralgia, even mild stimulation of your face — such as from brushing your teeth or putting on makeup — may trigger a jolt of excruciating pain.

Symptoms -

Episodes of severe, shooting or jabbing pain that may feel like an electric shock
Pain affecting one side of the face at a time, though may rarely affect both sides of the face
Pain focused in one spot or spread in a wider pattern
Constant aching, burning feeling that may occur before it evolves into the spasm-like pain of trigeminal neuralgia
Pain in areas supplied by the trigeminal nerve, including the cheek, jaw, teeth, gums, lips, or less often the eye and forehead

Causes -

In trigeminal neuralgia, also called tic douloureux, the trigeminal nerve's function is disrupted. Usually, the problem is contact between a normal blood vessel — in this case, an artery or a vein — and the trigeminal nerve at the base of your brain. This contact puts pressure on the nerve and causes it to malfunction.
Trigeminal neuralgia can occur as a result of aging, or it can be related to multiple sclerosis or a similar disorder that damages the myelin sheath protecting certain nerves. Trigeminal neuralgia can also be caused by a tumor compressing the trigeminal nerve.
Some people may experience trigeminal neuralgia due to a brain lesion or other abnormalities. In other cases, surgical injuries, stroke or facial trauma may be responsible for trigeminal neuralgia.