Facial sagging can be caused by a variety of factors, some resulting in permanent droop and others that can be overcome through facial exercises. The outer skin, or epidermis, of the face is attached via the hypodermis to the underlying muscle, and it is this muscle in conjunction with your skin's natural elasticity that determines the tautness of your face. Injury, infection and gravity can all affect the condition of those muscles.
Age affects both your facial muscles and your skin. Beneath the weight of skin and fat, the muscles can stretch and sag over time. The loss of skin elasticity can also contribute to a sagging facial appearance. Factors such as sun damage and smoking -- in addition to age -- can contribute to the breakdown of the collagen needed to maintain skin elasticity.
Repetitive facial movements such as those made when smiling or eating work specific muscles and leave some muscles underdeveloped, which may contribute to sagging in those areas. The muscles of the face, like those in other parts of the body, require contraction and resistance to maintain their strength.
Injury and Stroke
Full or partial facial sagging may result because of nerve injury or stroke, reports CNN Health. In the latter case, the loss of blood supply to the brain due to a blockage or hemorrhaging leads to the death of brain cells, which may cause paralysis in the face and other parts of the body.
According to HealthHype.com, diseases such as Bell's Palsy can cause facial drooping when facial nerve endings are inflamed due to viral infections. Suffering from herpes simplex and upper respiratory tract infections may make you more prone to Bell's Palsy. Ramsay Hunt syndrome is another disease leading to facial sagging that can result from an infection of the virus that causes chicken pox.