Black Heads, White Heads
These are also known as comedones. These are the first lesions of acne and occur due to blocking of hair follicles with oil and dead skin cells. When the follicle is open they form black head due to entrapment of dirt and when closed they form white heads.
The primary reason for the same is hormonal changes.
These get aggravated by:
Oral and topical medications
Extraction of black heads, white heads
These are also known as comedones.