Oil, dead skin cells and bacteria block pores and cause small bumps called blackheads or whiteheads. If a blocked pore stays open, it can look kind of black and is called a blackhead. If a blocked pore closes up, the top of the bump looks more white. So it's called a whitehead. Blackheads and whiteheads are pretty easy to treat. You probably can use stuff you buy at the store. If these are the only kind of pimples you have, it's not so bad.