Turgor and Colloid
Turgor refers to the state of liquid and colloid just under the skin. Colloid is a liquid thickened with proteins. The role of colloid in the appearance of skin has been well known. Many expensive cosmetics promise to restore the colloid in the skin by external application--but if this happens at all it happens very minutely. Skin that is naturally supported by colloid from within looks healthy. The appearance stems not just from the skin, but from the substrate the skin sits upon. The skin will look full, and while it will not look moist it will not look dry. Skin that is not underlain with with colloid will look less supported and dry. It is from this that the folk-term 'dried out' gets applied to someone in whom life force is low.
Wilhelm Reich proposed that during parasympathetic expansion, the body thickens the liquid near the surface and the liquid at the core became relatively more watery. During sympathetic contraction, the opposite happened, liquid towards the center became thicker and at the skin more watery, which produced a change in turgor.
The most important point of Reich is that skin with better turgor is more sensitive, more responsive, and more capable of pleasure.
There is a condition called edema, which results from poor circulation or local injury. In edema, a watery substrate accumulates under the skin at higher pressure, usually causing swelling and hardening. This is different from colloidal turgor at more normal and supple pressures. When someone is said to look radiant, good turgor seems to be a factor.