Why does cheek twitch?

Related to stress: The small muscles in either upper or lower eyelids may sometimes twitch. This is referred to as benign blepharospasm. Most often this is due to stress or stimulants like caffeine or nicotine. Reducing intake of stimulants or trying to reduce stress may help. These are typically self-limited.

Many reasons: This can range from bad teeth, ear infections, salivary gland problems, tmj, sinus infection or evenblepharospasm.

If the lip or mouth: Is involved, that is not blepharospasm or myokymia. It could be facial hemispasm. Consider further workup if persisting more than 3 months.