A boil is a deep skin infection that forms an abscess beneath the surface, while a pimple is a shallow blockage in a pore that stays closer to the top layer of skin. Both can look red and inflamed, but they differ in size, depth, cause, and how they need to be treated. Knowing which one you’re dealing with helps you avoid making it worse.
How They Look and Feel
Most pimples range from the size of a nail head to the size of a pea. They form small, pus-filled bumps on the skin’s surface that may be red, warm, or mildly tender. Some deeper pimples sit under the skin without a visible head and can feel hard to the touch, but even these stay relatively small.
A boil starts as a firm, painful, red lump under the skin and grows from there. Unlike a pimple, a boil can swell to the size of a golf ball and may ooze both pus and clear fluid as it matures. The pain is typically more intense and throbbing, and the surrounding skin often feels hot and tight. If you’re unsure which one you have, size and pain level are your two best clues: boils are bigger and hurt more.
What’s Happening Under the Skin
Pimples form when a pore gets clogged with oil and dead skin cells. The bacteria naturally living in your pores feed on that oil and multiply, triggering mild inflammation. The infection stays shallow, limited to the hair follicle itself or the very top layers of skin.
Boils go deeper. They’re caused by Staphylococcus aureus, a more aggressive bacterium that’s commonly found on the skin and inside the nose. This bacterium pushes past the hair follicle into deeper tissue, forming a pocket of pus, or abscess. The body walls off the infection, which is why boils feel like a firm, painful knot before they eventually soften and come to a head. When several boils merge into a connected cluster, that’s called a carbuncle, and it usually signals a more serious infection.
Where They Tend to Show Up
Pimples are most common on the face, forehead, chest, and upper back, wherever your skin produces the most oil. Hormonal changes, stress, and certain skincare products all contribute to breakouts in these areas.
Boils favor spots where friction and sweating overlap. The armpits, groin, buttocks, thighs, waistline, and back of the neck are the most typical locations. They can appear on the face too, but finding a large, painful lump in a friction-prone area like your inner thigh or armpit is a strong sign you’re dealing with a boil rather than a pimple.
How to Treat Each One
For pimples, over-the-counter products with benzoyl peroxide are considered first-line treatment for mild to moderate breakouts. Benzoyl peroxide kills the bacteria inside clogged pores and helps reduce inflammation. You apply it directly to the affected area, and most surface-level pimples clear up within a week or two. Deeper pimples without a head can take several weeks to resolve.
Boils need a different approach. The most effective home treatment is a warm compress: press a warm, damp washcloth against the boil for about 10 minutes, several times a day. This increases blood flow to the area and helps the boil soften, come to a head, and drain on its own. Many boils resolve with this method alone, though larger ones sometimes need to be drained by a healthcare provider who makes a small incision and packs the wound. Topical antibiotics like mupirocin are sometimes used to prevent the infection from spreading to surrounding skin, but they can’t penetrate deep enough to clear a boil on their own.
Why You Shouldn’t Squeeze Either One
Popping a pimple can push bacteria deeper into the skin, causing more inflammation, darker marks (post-inflammatory hyperpigmentation), and permanent scarring. On the face, the stakes are even higher. The area between your eyebrows and upper lip, sometimes called the “danger triangle,” has blood vessels that connect directly to the brain. In very rare cases, squeezing an infected bump in this zone can lead to a serious blood clot, brain abscess, or meningitis.
Squeezing a boil is riskier still. Because the infection already sits deep in the tissue, applying pressure can force bacteria into the bloodstream or into surrounding tissue, potentially causing a larger abscess or spreading the infection. If a boil needs draining, that should happen in a clinical setting with sterile instruments.
Signs of a Spreading Infection
A typical pimple, even an annoying one, doesn’t cause symptoms beyond the bump itself. Boils occasionally do. Red streaks radiating outward from the lump, increasing warmth, or swelling that keeps expanding are all signs the infection is moving beyond the original site. Fever, rapid heartbeat, unusual fatigue, loss of appetite, or vomiting suggest the infection may be entering the bloodstream. Multiple boils appearing at the same time, or boils that keep coming back, can indicate that Staph bacteria have colonized your skin and may need a more comprehensive treatment plan.
Quick Comparison
- Size: Pimples are nail-head to pea-sized. Boils can grow as large as a golf ball.
- Depth: Pimples sit at or near the skin’s surface. Boils form deep abscesses beneath the skin.
- Pain: Pimples may be mildly sore. Boils are typically quite painful, especially before they drain.
- Cause: Pimples result from clogged pores and mild bacterial overgrowth. Boils are caused by Staphylococcus aureus infecting a hair follicle deeply.
- Location: Pimples favor oily areas like the face and chest. Boils favor friction zones like the armpits, groin, and buttocks.
- Treatment: Pimples respond to benzoyl peroxide and surface-level care. Boils need warm compresses and sometimes professional drainage.