When you were a teenager, you likely spent some time in front of a mirror, staring at something you knew was about to appear on your face.

First, you notice a bump forming just above your lip. Or maybe it’s on your chin or your nose. Then you feel a pus-filled whitehead forming and you can’t wait to pop the heck out of it. Surely you’ve popped a pimple or two in your life, and may even still do it as an adult. But dermatologists say that you should resist the urge.

That’s because popping pimples can leave you with scars, or worse, an infection. When you pop a pimple, you’re actually tearing open your skin in the process. You’re also introducing bacteria from your hands into the open wound, which can then become infected, leave a permanent scar, or make you very ill.

In fact, there’s something called “the triangle of death” on your face — it’s so called because getting an infection in this area is dangerous and possibly life-threatening. Blood vessels in this area drain to the back of your head, at the base of your brain. This area also opens up to the sinuses. If not treated right away, an infection in your sinus cavity can be very serious, leading to paralysis, loss of vision or worse.

It’s because these veins around the nose, mouth and eyes are so close to the brain that bacteria introduced to your face basically gives those bacteria free rein to wreak havoc. A cut on your finger wouldn’t necessarily be quite as dangerous.

There's also a chance that what you think is an acne-related pimple might be a symptom of a skin infection called cellulitis. The infection is caused by bacteria such as staph or strep and usually is marked by red, swollen, painful skin. But you may also have symptoms like blisters and pimples. Trying to "pop" these swellings could spread dangerous bacteria throughout your body, causing more serious complications.

Other things to avoid

While we're talking hygiene habits, you may want to skip pulling out your nose hairs. The nose is full of harmful bacteria that is trapped there by tiny hairs called cilia. They’re there to prevent the bacteria from getting further into our body so, in a sense, a nose full of hair is actually your best line of defense against airborne infection. Of course, if hairs start sticking out of your nose and you must trim, it’s best to use an electronic hair trimmer that gently trims the hairs as opposed to yanking them out at the root, causing your nose to bleed.

Avoid picking at scabs on your face too. If you start to notice an infection, make sure to seek treatment from a doctor right away.

And finally, don’t pick your nose. If you must dislodge something from your nose, use a tissue. Picking your nose can introduce the same bacteria to your brain just as fast as popping a pimple can. So stay healthy, and keep your hands off of your face.

Editor's note: This story has been updated since it was originally published in August 2013.