The symptoms of syphilis growing on the tongue mainly include oral mucosal plaque and hard chancre. 1. Oral mucosal plaque: usually caused by stage 2 syphilis, the symptoms are mainly red infiltrative patches on the back of the tongue, or even vesicles, oozing, covered with a layer of grayish-white membranous material, and painful symptoms will appear after secondary infection. 2. Chancre: The chancre of the tongue is found in a small number of patients with stage I syphilis, and may be the result of direct contact with syphilis spirochetes through the mouth, leading to invasion of the oral mucosa and the formation of a chancre on the surface of the tongue. In the early stages of the chancre of the tongue, erythema and papules appear on the surface of the tongue, quickly forming localized vesicles and rounded ulcers with clear borders, accompanied by marked erythema and oedema, but with little pain. There is a plasma secretion at the site of the noma, and the ulcerated area is cartilaginous and hard to the touch, making it highly contagious. If you suspect that you have contracted syphilis, go to the STD department of a regular medical institution for diagnosis and treatment as soon as possible to avoid progressive aggravation of the condition and more serious consequences.