Cysts (fluid-filled tissue pockets), infections, and swollen lymph nodes commonly cause armpit lumps. Finding a lump in your armpit can be worrisome, especially if it hurts or appears unexpectedly.

A 27-year-old man will have a scar on his face for the rest of his life, after what he thought was a pimple turned out to be an infected cyst. In late 2024, Kai Davidson noticed a small lump on the ...