The hygienist said I clench during the day too. I didn't believe her. You can't catch yourself doing it. My jaw was tight at 7:30 in the car and I never noticed until the knot under my left ear showed up at 2pm.
The ring presses a point your hand and your jaw are wired to, the way a kid's loose grip stays loose because nothing is fighting it.
Within 2 weeks my jaw wasn't braced behind my face all day. π
See the ring that loosened my jaw