A 15-year-old girl complains of throbbing pain and a swelling above her upper lip, fever of 38.0°C, and deterioration of her general condition. Two days ago, she tried to pop a pimple in this area on her own. Objectively, she has a dense painful infiltration on the skin of her upper lip. The infiltration is rounded, cone-shaped. up to 2.5 cm in diameter. The skin over the infiltration is sharply hyperemic, with a necrotic rod in the center. Make the diagnosis.