They are 1-3 mm large balls and typically appear on the forehead and cheeks. In the middle there is typically a small dip. The color is often slightly yellow, and small blood vessels can be seen. It is common for a person to have several on their face at the same time. They do not cause problems beyond the cosmetic.
This is an enlarged sebaceous gland. Age and heredity are often predisposing factors. It probably comes easier to people who have been in the sun a lot. Some medicines have this as a side effect, for example immunosuppressive tablets such as ciclosporin. Sebaceous gland hyperplasia is a benign skin change, but can sometimes look quite similar to basal cell cancer (basal cell carcinoma).
They can be burned away with a laser, and laser treatment can be effective. Freezing treatment is also an option. On rare occasions, one can try tablets used against acne (isotretinoin).