A boil is a painful skin infection caused by bacteria that starts in a hair follicle or oil gland. Boils most commonly occur on the neck, armpits, shoulders, buttocks, and face. They are precipitated by factors like diabetes, poor hygiene, and skin irritation. Treatment involves applying warm compresses, draining pus, administering antibiotics, and using homeopathic remedies like Belladonna or Hepar Sulphur to bring the boil to a head and aid healing. Preventing the spread of infection requires cleaning clothes and wounds as well as maintaining good hygiene.