What condition is most likely diagnosed in a patient with multiple white lesions on the tongue accompanied by a fever?

The presence of multiple white lesions on the tongue, particularly when accompanied by fever, is characteristic of Primary Herpetic Stomatitis. This condition is caused by the herpes simplex virus (HSV), typically HSV-1, and is commonly seen in children during their first exposure to the virus. The lesions are soft, painful, ulcerated, and can appear on the tongue, gums, and other oral mucosa. The systemic symptoms, such as fever, often accompany this viral infection as the body mounts an immune response.

Oral Thrush, caused by Candida species, typically presents as creamy white lesions that can be wiped off, and it might not be accompanied by fever. Oral Lichen Planus is a chronic inflammatory condition that can produce white lesions but usually does not present with fever and tends to develop in older populations. Leukoplakia is a term used for white patches that cannot be wiped off and is often a sign of precancerous changes; it does not typically present with fever and is more common in individuals with risk factors such as tobacco use. Therefore, Primary Herpetic Stomatitis is the most likely diagnosis in this scenario due to the combination of white lesions and fever.