If bacteria from a boil get into the bloodstream, they can cause blood poisoning. It can be dangerous to squeeze a boil around your lips or nose because the infection can be carried to the brain. Other danger zones are the armpits, groin, and the breast of a nursing woman.
If the boils is extremely tender or under thick skin like that on the back, or if the boil victim is very young and or old or sick, have a doctor treat it. If there are any red lines radiating from it, or if you feel any general body symptoms like fever and chills or swelling of lymph nodes, see a doctor because the infection may have spread. Diabetics are especially prone to such dangerous boils. it many need a course of antibiotics. sometimes recurrent boils can be symptoms of more serious diseases.