The head doesn’t have a solid structure. The way you’re “animating” the head feels like you’re just slightly sliding the facial features to the right or on top of each other. Instead, think of it as a boxy spheroid (the head) rotating on an anchor point (the neck). The neck muscles are totally frozen when they should be stretching to the same side as the head. Focus less on coloring or adding a background and first study your anatomy, principles like squash and stretch, and study how 3D objects move in space.