I'm afraid it won't stop!
Breathe. Panic will make something like this worse. I would recommend distracting yourself. Watch a show, play a game, read a book, listen to music, etc. If at any time your eyes want to unfocus, then let them unfocus without fighting it. Removing the fear around the action will make it less taboo, and after a while you'll likely stop thinking about it and it will stop happening.