Over the past couple of months, i have been noticing a lower lip twitch off and on. what could be causing this?

Myokymia?: Random twitching of an eyelid or another small facial muscle, which happens in normal people, is called myokymia (an involuntary, spontaneous, quivering of a few muscle cell bundles within a muscle). Myokymia starts and stops spontaneously. It can last a few minutes to a few days. One should see a doctor if such symptoms persist, keep recurring, or are combined with any other symptoms.