What's in a zit? How pimples form and what different acne types are made of

• Pimples are clogged with dead skin cells, oil, and bacteria that lives on the skin.
• More severe pimples are inflamed and filled with pus.

Pimple popping videos are disgusting. Period. And yet — for the millions of people who can't stop watching them online — they're also deeply satisfying. There's just something cleansing about seeing so much gunk removed from the human body.

But even if you're a seasoned popaholic, you might not know where all that pimple gunk comes from — or what's it's actually made of.

It turns out that what's inside a pimple actually depends on what type of pimple you're talking about. Here's the full breakdown.

Blackheads and whiteheads

Blackheads and whiteheads are both clogged with the same thing: Dead skin cells (which your skin is always shedding), Propionibacterium acnes (a bacteria that lives on your skin), and sebum (an oily substance secreted by tiny glands inside your pores).

A lot of people think blackheads are clogged with dirt, but that's not true. The color difference between these two types of pimples actually has to do with oxygen,the National Institutes of Health explained.

In whiteheads, the clog stays below the surface of the skin and remains white. But in blackheads, the clog is open to the air. It turns brownish-black when it's exposed to oxygen.

Both whiteheads and blackheads can stay in your skin for a long time if you don't pop them. Lovers of popping videos know sometimes pimples get really big.

Papules and pustules

Sometimes, a clogged pore gets so irritated that its walls break, and the body sends white blood cells —the fighters of your immune system— to start addressing the damage. This causes redness, pain, and inflammation.

That's when you can end up with pimples called papules or pustules. Papules are closed red bumps that are hard and sometimes painful the touch. Pustules are what most people think of as a zit: Red and inflamed with a white head at the center. The stuff you squeeze out of them is pus, which contains dead white blood cells.

Cysts and nodules

Cysts and nodules — the most severe type of acne — are essentially just bigger, angrier, more irritated versions of papules and pustules, the American Academy of Dermatology explained. Both are inflamed, painful, and lodged deep in the skin, but cysts contain pus.

Popping pimples on your own is usually a bad idea

Most authorities, including the AAD, say you should always let a dermatologist pop pimples for you. The DIY approach might make for awesome YouTube videos, but the bacteria on your hands can get into pimples and give you an infection. Plus, at-home popping without proper technique can make a pimple worse or leave you with permanent scarring.

Doctors can extract smaller pimples using tools like the comedone extractor (just like Dr. Pimple Popper!). More severe acne, like nodules and cysts, can be injected with medicine that makes swelling go down, or they can be cut open and drained.

But if you can't make it to a dermatologist, the AAD recommends patience. Avoid popping or picking at your skin, use ice to quell pain and swelling, and try over-the-counter treatments to speed up healing. Here are 18 products that really work.