That solid stuff is primarily pus, a mix of dead skin cells, trapped oil (sebum), bacteria (like C. acnes), and your body's infection-fighting white blood cells and debris, all forming in a clogged pore as part of your immune response to inflammation, but it can also be sebum/dead cells (sebaceous filaments), keratin plugs, or even milia depending on the bump.
That white, hard material you see when popping pimples is primarily pus—a mixture of dead white blood cells, bacteria, and debris. Pus is essentially your body's response to infection or irritation caused by clogged pores.
You may be tempted to pop this unwanted guest, but it's not a good idea. Contrary to what pimple popping videos may show, squeezing your skin to extract the contents of a pimple — a mixture of oil, dead skin and bacteria — can cause scarring and infection.
Pimples refill after popping because you often don't remove all the pus and debris, pushing some deeper, while the inflammation continues, and the pore wall itself can be damaged, allowing oil (sebum) and dead cells to collect again, leading to recurrence in the same spot. Popping also creates an opening for bacteria, causing more inflammation and new pimples nearby.
Additionally, popping a pimple can lead to a nodule (hard, red, painful blemish deep within the skin) or a cyst. The most serious form of a blemish, cysts are large and painfully inflamed lesions.
Milia are small white seed looking bumps. They are different than blind pimples because you can see the hard rice looking “seed” of packed keratin inside them. This is because they are closer to the skin's surface than an inflammatory acne papule is.
The trauma caused by the squeezing can also cause blood vessels underneath to burst, causing the pimple to fill with blood. Regular pimples occur when the skin's pores become clogged with bacteria, sweat, or dirt. More severe acne can be due to hormonal changes in adolescents and adult women.
Treating deep, painful pimples: Dermatologist tips
You've probably heard that squeezing or picking at a pimple is not a great idea, and the same goes for sebum plugs. By squeezing, you can push the contents deeper into the skin or break the pimple open, which allows the bacteria inside the pimple to spread and any bacteria on your hands to enter the pore.
In acne, the glands begin to produce too much sebum. The excess sebum mixes with dead skin cells and both substances form a plug in the follicle. If the plugged follicle is close to the surface of the skin, it bulges outwards, creating a whitehead.
Known also as cystic acne, hard pimples arise when skin pores become clogged with oil, dead skin cells, and bacteria. This blockage, occurring deep within the hair follicle, leads to infection and inflammation, forming a hard lump beneath the skin's surface.
Many people believe popping a pimple helps it heal faster, but the opposite is true. Pressing on a blemish can push bacteria, oil, and debris deeper into the skin, leading to more inflammation, swelling, and an increased risk of scarring.
Common ways include the use of a topical retinoid cream such as tretinoin, tazarotene or adapalene; removal with a sterile lancet or scalpel followed by the use of a comedone extractor, a tool used to remove whiteheads and blackheads; a series of fruit acid peels or microdermabrasion procedures; and carbon dioxide ...
Milia (singular: milium) are small keratin-filled cysts that form just beneath the surface of the skin. Unlike acne or whiteheads, they're not caused by clogged pores or bacteria. Instead, milia develop when dead skin cells become trapped instead of naturally exfoliating—creating hard, pearl-like bumps under the skin.
Symptoms of keratin plugs include small bumps, usually on the upper arms, butt, thighs or cheeks. You might mistake a keratin plug for acne. But they aren't the same as pimples. They often develop in clusters or groups and feel rough (like sandpaper) when you touch them.
On the other hand, bumps caused by STDs, like herpes sores or genital warts, are often accompanied by pain, itching, or changes in appearance, and they tend to appear near the vulva, vagina, and anus.
When a pimple is not properly extracted, the underlying infection may remain, leading to the pimple refilling with pus. It is crucial to refrain from squeezing or popping pimples forcefully, as this can worsen the infection and increase the risk of scarring.
A sebum plug is due to excess sebum or an accumulation of dead skin cells. They commonly appear on the chin or forehead and stick out of your skin. They may seem harmless at first glance, but sebum plugs on the skin's surface can lead to bacteria buildup, redness, inflammation, acne, and breakouts.
How are milia treated?
The other half of the pus gets sucked inside since you're putting pressure when you release. It just stays there. You can't get it out anymore because it's inflamed and irritated. That's why pimples come back on the same spot, sometimes bigger than the one before it.”
Clean the pimple and the skin around it as well as your hands, and use a sterilized needle to pierce the pimple. Apply gentle pressure while pulling away from the pimple with tissue- or cotton-wrapped fingers. Afterwards, clean the area again and apply an antiseptic.
Various at-home treatments can help to resolve hard pimples, including topical creams with benzoyl peroxide or salicylic acid, warm compresses to encourage the pimple to surface, and ice packs to reduce swelling and pain.