If done incorrectly, squeezing blackheads can result in pitting of the skin or permanent red scarring. However, squeezing done correctly often is an effective method of removing the dirt and sebum trapped beneath the skin that causes blackheads.
The recommended method for squeezing a blackhead is to place the fingers beneath the blackhead and to push upward. Squeezing the fingers together results in trauma to the skin and frequently leaves traces of dirt behind.
A blackhead's sebaceous matter should not be forced to the surface. Rather, gently squeezing, especially after steaming the area, should coax the debris out of the pore.