Boils, or boils, are caused by Staphylococcus aureus infection of the human skin. The pathogenic bacteria breed and multiply in the soft tissues, pores or sweat glands of the skin and continuously secrete toxins, thus eroding the normal cells of the body, which in turn produce an inflammatory response that causes local tissue redness, swelling, and increased skin temperature with intense pain. The appearance of a white head on the surface is not necessarily a sign of maturity. Although in most cases a white head appears when a boil matures, it may also be caused by a local swelling of the boil when it is still immature and tops out the acne in the pores: 1. Mature boil: When a white pus head appears locally and has a certain fluctuating sensation when touched, it means that the boil has matured. If the pus is discharged, the boil will gradually crust over and heal. 2. Protruding pimples: If the pimples are hard when pressed and there is no obvious fluctuation, this is not a sign of a mature boil, but only a protruding pimple, especially for people with large pores. It is also possible that the boil may become inflamed and show a prominent white head, which is similar to the appearance of a mature boil and can be easily confused.