The functions of skin are as follows:

• Sensation: The primary sensory organ for pain, pressure, touch, and temperature.
• Heat Regulation: The body temperature is regulated by sweating to reduce heat buildup and shivering to combat cold.
• Absorption: Certain lotions, oils, and medicines can be absorbed
  through the skin.
• Protection – Too much UV light can damage the skin, thus to defend itself, the skin produces Melanin, a pigment that gives skin its tan.
• The Acid Mantle is a defence mechanism that keeps germs and
  bacteria out of the skin. Moreover, this barrier aids in preventing
  moisture loss.
• Excretion: Through the sweat glands, the body rids itself of waste and pollutants.
• Secretion: Sebum and perspiration are secreted onto the skin’s
  surface during secretion. The perspiration and sebum combine to
  generate the acid mantle, which keeps the skin supple and
  moisturised.
• Production of Vitamin D: The body needs vitamin D for the
  development of strong bones and clear vision. Vitamin D is produced in the body when UV rays from the sun are absorbed.