How does facial aging happen?

There are two main influences on any biologic process whether normal (physiologic), or abnormal (disease). This is also at the heart of the age-old question of nature versus nurture with respect to development. Genetic composition can influence the rate of loss of soft tissue (loss of glycosaminoglycans, proteoglycans,), loss of elasticity (elastin), and thus hasten environmental effects on aging. The most impressive illustration of the degree to which genetics influence aging can be found by examining progeria. This disorder involves accelerated aging of most organ systems including skin. Other genetic disorders that may predispose to skin laxity include problems with collagen (i.e. Ehlers Danlos), or elastin (i.e. Cutis Laxa). Environment plays a role in facial aging mainly in the form ultraviolet radiation. Photoaging is mediated through the generation of free radical species, significantly reactive substances that not only cause damage to the structural elements of skin, but have a self propagating nature. So, genetics and the environment are both responsible for your aging skin.