A 27-year-old patient has been referred for endodontic treatment on the 45 tooth. Objectively: the tooth crown is decayed, the lateral surface of tongue and cheek mucosa being in direct contact with the 45 tooth are covered with grayish plaques of macerated epithelium that are somewhat raised above the surface of the mucous membrane. Uvula and palatine arches are of dark red colour, and the hard palate has papules with a red rim and covered with grayish epithelium. Submandibular, cervical, supraclavicular, subclavicular lymph nodes are enlarged, painless. What is your provisional diagnosis?