People with acne
may have different types of bumps on their skin. These can be whiteheads, blackheads,
pimples, and cysts. Where do they come from? Your skin is full of tiny holes called
pores. If a pore gets clogged with oil, dead skin, and bacteria, the pore may close
and form a whitehead. If a pore gets clogged but stays open, the top surface can darken
and you're left with a blackhead.