When a follicle ruptures deep within the dermis, irritating oil and dead
cells seep into the surrounding area and a cyst forms. The cyst appears as a
large, hard, and painful lump underneath the surface of the skin. A cyst is a severe
pimple that takes a longer time to reach the surface of the skin. As the cyst works its
way to the surface, it destroys many live cells and will often leave permanent scars.
These scars are often referred to as acne pits. Quite often a wall (membrane) will
form around the debris and medical treatment may be needed to clear the condition .