Or make it seem smaller? Thanks.
Due to the size and diffuse anatomy of this muscle, it is not practical to debulk the muscle. In some instances the activity can be weakened via use of botulinum toxin. However, this is usually limited to the lip border and most commonly the upper lip only.
There is no way to reduce the size of the orbicularis oris. It is a circular functioning muscle of the mouth. It cannot be cut or removed for fear of paralysis from smiling.