Cellulitis is a bacterial infection on the skin. The symptoms include pain and swelling, the skin will look red, and is often warm to the touch. Sometimes it will develop blisters. The person may also develop a fever. Cellulitis usually occurs on the legs, but it can appear on other body parts. If it is not treated, it will infect the lymph nodes and blood stream and it can kill you. Treatment should be started as soon as possible.