Cosmetic Surgery and Plastic Surgery are closely related and almost the same thing but there is a difference.
Cosmetic Surgery is a unique discipline of medicine that is focused on the enhancement of a persons appearance through surgical and medical techniques.
Plastic Surgery is more of a reconstructive surgery and is used to fix and correct areas of the body that are dysfunctional.
Cosmetic Surgery is performed to reshape normal structures of the body, usually to improve form and appearance while Plastic Surgery or Reconstructive surgery is performed on abnormal structures of the body, that are caused by congential defects, developmental abnormalities, trauma, infection, tumors or diseases.