The application of heat is the most common and effective home remedy for getting rid of boils under armpits, according to MedicineNet. Soaking the affected armpit in hot water or using a hot pack can work to increase the circulation in the area where the boil is located. Heat allows the body to fight the infection of the boil by drawing white blood cells and antibodies to the infection site.
If boils are firm and small, it is not a good idea to open the area around the boil or drain the boil, even if pain is being experienced. Inversely, when a head is formed on the boil and it becomes soft, draining it can bring a dramatic relief for pain. Hot soaks usually treat most small boils that tend to form around hairs.
Larger boils oftentimes require medical intervention. Health care providers can lance large boils and drain them of their pus, according to MedicineNet. A doctor may need to be consulted on larger boils in some cases that require a prescription for antibiotics. Not all incidences of boils warrant antibiotics, since antibiotics are not helpful in all situations and may not work for all boils.