Why does it happen? Well, skin has little glands, which produce natural oils that keep our hair and skin looking nice.
When a pore (the opening of a gland out onto the surface of your skin) gets clogged with dead skin, the gland gets irritated — either by bacteria that’s trapped inside, or by continuing to produce its natural oils, which now cannot get out.
It gets inflamed (making the red bump). The body’s defense system will wall off the gland to isolate the problem, and eventually the skin on top of it thins and breaks open, getting the gunk out of your body. Whiteheads, blackheads, and pimples are actually just different life-stages of the same issue.
Now the important question: what can you do about it? There are three topical drugs for acne and they all work the same way. They break down the proteins that help your skin cells stick together, which means skin cells slough off more easily, thinning the skin. This speeds up the process of getting the zit up to the surface and out.
Every over-the-counter acne treatment — whether you buy it in Sephora or Walgreens — will have one of two active ingredients: benzoyl peroxide or salicylic acid (which is similar but not the same as aspirin). Since the active ingredient is what’s important, you can buy an equally effective treatment at either Sephora or Walgreens. I’m liking Neutrogena Rapid Clear Acne Eliminating Spot Gel, a clear gel with a 2% salicylic acid concentration (~$8-9 at Walgreens).
The third drug is a retinoid (like tretinoin, the active ingredient in Retin-A) — these are similar but not the same as vitamin A. Retinoids are prescription-only because they can cause major birth defects.
Because all these drugs thin the skin, they usually carry a warning about increased risk of sunburn. Going overboard (applying too strong a concentration, applying too often), can result in peely, flaky skin. Chemical peels work by the same mechanism, but more of it, which is why you don’t do them at home — you could end up going too far and scarring yourself. I hate pimples as much as anyone, but time and patience are also necessary to cure them without hurting your skin. If what you’re doing hurts, stop doing it.
One more note: some people have constant acne that just won’t go away. It’s okay to see a dermatologist about this. IF (and only if) your acne is caused by bacteria, your doctor may put you on a class of antibiotics called tetracyclins to kill the bacteria. If your acne is not caused by bacteria, the antibiotics will be completely ineffective. Don’t self-prescribe antibiotics, and if you are prescribed them by a doctor, please for the love of God, follow the dosing instructions and take the full course.