Some people think they're filled with dirt. But really, the content of the clogged pore can appear black as a result of dark pigment or oxidized oil , not because of dirt. What we all know as pimples are really inflamed lesions. This is caused by the bacteria that live in a healthy follicle, and can break down when the pore's been plugged. Little irritants found inside the pore get everything worked up and inflamed.
Pimples pop up for a bunch of reasons.
Your hormones are one of the reasons for your pimples, especially when you are under stress. As you grow your body undergoes a lot of hormonal changes. And if you are thinking about how to stop the changes, well, you can't. And if you knew how hormones helped in growing, you wouldn't want to. As you grow towards adulthood, these hormones start triggering off a set of reactions, even under the surface of your skin.