A 35-year-old man has developed edema and hyperemia that first appeared in the area of his wings of the nose and eventually spread to the upper lip and checks. Examination detected a fissure in the area of the lower external edge of the left nostril. The skin there is taut, dense, purple-blue, with smoothed out pattern. The local temperature is elevated. Palpation is painful. The affected area has clear irregularly-shaped margins. Make the provisional diagnosis: