What exactly is happening when your rosy hue is due not to an adorable blush but to a gang of pimples taking up residence in your face? (For those of you allergic to gross but fascinating sciencey stuff, skip the next paragraph.)
A surge in your body’s testosterone level causes your sebaceous glands to excrete an excess of a skin-protecting enzyme called sebum, clogging your pores and attracting hungry bacteria. These bacteria then release toxins that invade the pore lining, causing a bacterial infection. Your skin turns red as blood rushes to the area, and white blood cells swarm the scene to destroy all the bacteria, before dying honorably.
According to science, anyway! But we think there's more to the story (how could our bodies actually be this gross?). Here are some way more likely/slightly less disgusting explanations for that chin breakout that caused you to bring scarves back into fashion in June.