A very common condition for the tongue is called geographic
tongue, where there is swelling
in various areas
and not
in others
and often redness
and tenderness. Also, there can be fungal infections of the tongue. Throat cancer would not be present as an acute problem, and especially not just on the tongue. If this continues, I would recommend that you see your dentist. They would be perhaps a better resource than the STD clinic. I'm sorry I can't help you more with this question.