A 45-year-old male patient complains of inertness, headache, fever up to 39°C, burning neuralgic pain in the mandible on the right. Objectively: the skin of chin on the right is hyperemic, there is vesicular rash with a vesicle diameter of 1 to 6 mm. Similar vesicles can be found on the hyperemic oral mucosa on the right. They burst easily making erosions which are covered with fibrinous pellicles. Regional lymphadenitis is present. What is the most likely diagnosis?