As our faces age, so do our lips. The oral region tends to fall and sink. The loss of volume is only part of the explanation of this phenomenon, the degradation of the structure of the skin and its supporting tissue are so important.
The male face usually has a long upper lip with little or no visibility of the upper teeth. The juvenile female face is characterized by a shorter distance between the base of the nose and the upper lip with more visibility of the teeth.
It is a typical female trait that also characterizes youth, as opposed to the fall of the upper lip and the concealment of their teeth, which characterizes the aging process.