A 2-year-old girl has body temperature 38,5°C, a swelling below her jaw on the right. On the 5th day of illness there apeared rhinitis, cough, a small movable globule under her lower jaw on the right. Objectively: general condition of the child is moderately severe. The face is asymmetric due to the swelling in the right submaxillary area. The skin is hyperemic, glossy, there is a diffuse infiltrate in the right submaxillary area spreading to the upper neck parts on the right, it is dense and painful; the skin doesn’t make folds. Teeth are healthy. What is the most probable diagnosis?