Pus is a natural sign of your body fighting infection. Sometimes it's no cause for concern (like the pus in your average pimple, for instance.) However, infections that create pus can also be dangerous and even life-threatening. So on the scale of "pimple" to "rush to the hospital immediately," how dangerous is the pus in an abscessed tooth? We'll break down the causes, risks, and treatment, so you know what to do if you have a small unwanted sac of fluid in your gums.