Medical News Today states that boils are puss-filled lumps that most often appear on the face or neck. They can also be found around the groin, on the buttocks, and in the armpits. “A boil, medically known as an abscess or carbuncle, is a localized bacterial infection in the skin,” Dr. Roy Seidenberg, a board-certified dermatologist, explained to Byrdie. “Boils are caused by atypical mycobacteria or fungus, or even viruses which are less common and slower growing.” Boils can also be passed between people with poor hygiene.
Cysts, on the other hand, are not contagious. These are fluid-filled lumps that are typically benign in nature (via Medical News Today). One of the more noticeable, distinguishing differences between a boil and a cyst is that a boil may be painful to the touch, red, and swollen. Because a boil is a bacterial infection, you can also develop a fever or start to feel weak soon after its development.
If you find a new lump, make an appointment with your doctor to be on the safe side. They will be able to direct you toward the best form of treatment.