How do I cope with never knowing if my teaching stuck?

You can teach anyone to care for their own mouth. You are good at it. And there is a quiet grief in the work: they leave, and you rarely find out whether any of it stuck. You plant seeds and almost never get to see the garden. That not-knowing is a real ache for someone who gives as much as you do. But consider what teaching actually is. You do not own the outcome. You offer knowledge, and what someone does with it, over months you will never witness, is theirs. Some of what you taught took root in ways you will never hear about. The uncertainty is not proof it did not work. It is just the nature of giving something away. So let the grief soften into faith. Do the teaching well, offer it fully, and trust that some of it lives on out of your sight. And when a patient does come back better, let yourself really take it in, because that one is standing in for the many you will never see. You gave them something real. Not seeing where it lands does not make it any less given.