Though they're not cancerous, sebaceous cysts can be irritating.
A sebaceous cyst is a small lump or bump under the skin. This type of cyst is not cancerous.
They are most often found on the face, neck, upper back, and upper chest, but can occur on other sites of the body as well.
Usually a sebaceous cyst grows very slowly and doesn't cause pain.
However, they can become inflamed or infected, with the overlying skin becoming red, tender, and sore.
Sometimes, they occur on a site that is constantly irritated, such as a cyst on your neck that rubs against your collar.
In those cases, treatment can help reduce discomfort.
A cheesy, bad-smelling material sometimes drains from the cyst. And they can look bad cosmetically, especially if one develops on your face.