While Lewis structures are useful, especially when you're learning about valence, oxidation states, and bonding, there are many exceptions to the rules in the real world. Atoms seek to fill or half-fill their valence electron shell. However, atoms can and do form molecules that are not ideally stable. In some cases, the central atom can form more than other atoms connected to it. Also, the number of valence electrons can exceed 8, especially for higher atomic numbers. Lewis structures are helpful for light elements, but less useful for transition metals, including lanthanides and actinides. Students are cautioned to remember Lewis structures are a valuable tool for learning about and prediction the behavior of atoms in molecules, but they are imperfect representations of real electron activity.
the tooth cylinder that fits right between the nose and chin, can be simplified into a bloated tuna can. By bloated I just mean that the wall of the cylinder curves out rather than being flat. This comes into play when looking at the lips from any angle other than straight on. The bloated tuna can affects the surface forms of the lips. The center line of the lips gets pushed outward and when viewed from top or bottom, the lips wrap around the cylinder. Notice that from this angle, the corners of the lips are actually lower than the bottom of the bottom lip.
Try to avoid drawing the lips on a flat surface.