“Blackheads, also referred to as “open comedones” are small spots on the skin which surface when oil and dead skin clog the skin pores. When that spot remains closed, a whitehead bump forms (closed comedones). If the spot opens and is exposed to air, it becomes a blackhead. Blackheads appear most commonly on the face, but also on the back, chest, neck, arms and shoulders.” Continue to read here.
Credit: www.acneaction.ca