Sagging skin is the loss or deficit of muscle firmness and density. It occurs when there is a deficiency in elastin and collagen responsible for providing elasticity and firmness to the skin.
Aesthetic medicine is responsible for treating, restoring and maintaining physical appearance and beauty.
A dermatologist is a doctor who specializes in diseases of the skin, hair, nails and mucous membranes.
The plastic surgeon is the doctor who specializes in cosmetic and reconstructive surgery.
Remember that for the proper selection of health professional that treats sagging skin you must consider the nature, severity and symptoms you are presenting.