These lumps just beneath the skin, more appropriately called epidermal cysts, are common and harmless. The most important thing is to check with a doctor to properly identify them.
They are non-cancerous and not life-threatening, but they can be uncomfortable.
Skin cysts do not usually cause any problems, apart from their appearance. They are not usually tender, but their presence can be obvious to the touch.
If a cyst on the scalp catches on a brush or comb, for example, this may cause pain, but cysts are normally only painful if they become inflamed or infected.
Typically located on the head, neck, or torso, the cysts are firm, round, and sometimes movable, and grow slowly, sometimes to a few centimeters or more in diameter. They may be caused by injury to a hair follicle or other damage to skin. They are filled with a greasy material made of fat and keratin. There can be a familial tendency to developing sebaecous cysts.
If a cyst becomes infected or if you are bothered by it for any other reason, it can be surgically removed. This is a simple procedure, and usually requires stitches which are then removed in a few days. If it is only drained, it will probably quickly grow back again.
Lipomas can look like cysts, but are benign fatty tumors. They seem to run in families and also grow slowly. A doctor will often be able to tell you whether you have a cyst or lipoma by its look and feel, though you may need an ultrasound or other tests for a definite diagnosis. Lipomas can be removed if they are bothersome by being unsightly or uncomfortable.
While skin cysts can look bad, doing anything to them can make them worse. Picking, rubbing, or squeezing cysts is likely to cause damage and make any infection worse. It is also likely to increase the pain and worsen its appearance.
Dealing with skin cysts that are causing concern or producing symptoms means getting them seen by a doctor.