@Enexin
You mean the ones around the jaw area? To me it's just look like an artistic choice to represent clenched jaws, like when you clench your jaw the muscles in that area become visible for many people.
@sirflimflam
It's true that even though in the core we're still quite similar to out teenage selves, we do change, but that isn't necessarily a bad thing in a relationship with an age gap, like many thing it depends a lot on context, and I truly believe there can be really healthy and good...