TCM believes that the liver governs shu-xie (dredging and regulating), and the functions are dredging and regulating qi and blood and fluid in the whole body. If people are always in the stress, nervous and poor emotion states, he will be manifested as liver qi stagnation, causing qi and blood disorder and stasis, resulting in wax yellow and dark complexion. In TCM, the reasons of spleen affecting the skin are spleen governing blood, vessel and arms and legs, so, spleen is the source of life of qi and blood. So, the eating disorder and restless will affect digestion system, resulting in insufficiency of the spleen. As for kidney governs water in TCM, which means governs the balance of fluid of whole body. Continue to read Chinese medicine Treatment for Dermatomyositis.
So, overfatigue will cause vacuity fire flaming upward and static blood binging in the kidney, lead to rough and dark skin. The lung governs the skin. Due to "Lung dominates qi through out the body and Kidney is the base of qi", the deficiency of the kidney and insufficiency of the kidney water will affect lung functions, lead to poor complexion.