The bump may very well be a surface abscess, better known as a "boil," and popping it could only make things worse.
Boils occur when white blood cells rush to attack bacterial germs that have invaded bodily tissues, says a report in the January issue of Mayo Clinic Health Letter.
The body's immune system gets into the act by "walling off" the pus that's formed and building an abscess around it. The next thing you know, you've got a boil.
While commonly seen on the skin, boils can in fact occur inside your body.
So if it's on your skin and you shouldn't pop it, what can you do?
The experts recommend applying a warm, moist dressing to relieve the pain and swelling. Trying to pop the abscess may in fact spread the infection. If the symptoms don't subside in a few days, seek medical attention.
An internal abscess can be a more serious situation, possibly causing fever for five days or more, unexplained weight loss, night sweats or other localized symptoms. In such cases, it's important to see a doctor as soon as possible to prevent enlargement of the abscess and the spread of the infection.
Treatment for an internal abscess typically involves antibiotics and draining the pus.
Boils are especially common among athletes. Read more about boils, and other skin conditions, at the American Academy of Dermatology.