if not now, when

"An eyelid twitch is a general term for involuntary spasms of the eyelid muscles." [definitely involuntary. check.]

"The most common things that make the muscle in your eyelid twitch are fatigue, stress, and caffeine." [shoot. check.]

"Once spasms begin, they may continue off and on for a few days." [few days +. check.]

"Then, they disappear." [no check.]

"Most people experience this type of eyelid twitch on occasion and find it very annoying" [for sure. check.]