Sunken scars are recessed into the skin. They may be due to the skin being attached to deeper structures (such as muscles) or to loss of underlying fat. They are usually the result of an injury.
Acne & Chicken Pox Scars
A common cause of sunken scarring is acne or chicken pox which can result in a pitted appearance. However, it is important to note that acne scarring is not always sunken in appearance and can even become keloid.