Those are known as secondary behaviors. At some point, you contorted your face just a bit and got a feeling of relief from the struggle and that was enough to reinforce it so it got repeated and increased over time. https://stutteringtherapyresources.com/blogs/blog/addressing-secondary-characteristics-in-children-who-stutter Basically, you can take the tack of accepting your stutter and stopping the "struggle" (because the struggle not to stutter is what causes the facial behaviors), or you can work on the stutter itself. The McGuire program is pretty well regarded for what it's worth.