Boils Boils can occur anywhere on your skin, but appear mainly on the face, back of the neck, armpits, thighs and buttocks — hair-bearing areas where you're most likely to sweat or experience friction. Signs and symptoms of a boil usually include: 
A painful, red bump that starts out small and can enlarge to more than 2 inches (5 centimeters)
Reddish or purplish, swollen skin around the bump
An increase in the size of the bump over a few days as it fills with pus
Development of a yellow-white tip that eventually ruptures and allows the pus to drain out
 Carbuncles A carbuncle is a cluster of boils that form a connected area of infection. Compared with single boils, carbuncles cause a deeper and more severe infection and are more likely to leave a scar. People who have a carbuncle often feel unwell in general and may experience a fever and chills.