Imunofluorescence and histopathology would help.. Oral white lesions include leukoplakias , keratoses, leukoplakias of clear infective origin (candidal, syphilitic, hairy leukoplakia associated with Epstein-Barr virus), candidosis, lichen planus, oral submucous fibrosis, lupus erythematosus, congenital lesions (eg, white sponge nevus, dyskeratosis congenita, pachyonychia congenita), and frank carcinomas.
I think that is not a hard problem,and is about to mal abusing foreign bodh substances as warm,chilly etc,ended on destruction of superior layer of antero-superior surface tongue ,facing sweating glands
Oral Hairy Leukoplakia ... A lesion typically on the side of tongue, asymptomatic, nonremovable and is highly suggestive of HIV infection.