Okay so let's rationalize. You're 28 the demographic for HPV related oral cancer is usually 40's and up. This type of oral cancer is often detected in the nodes first and then they find the primary in the base of tongue (down the throat) or tonsils. Someone here can correct me if I'm wrong but we've never seen an HPV positive OC patient your age. So chances are it's not this type of cancer.

The other type - non HPV is a little trickier. It does pop up in the nodes but 99% of the time the primary is found on the oral mucosa (cheek, inside lip etc...)tongue or gums. I am assuming your dr. did a thorough examination. If there is a tumor or lesion on your tongue it's visible. Usually whitish red and often quite sore. on the gums and cheek it's visible though may be painless. This is often a heavy smoker and drinker's cancer.
There are younger people who get it, and people like me who have no precursors. But we are rare.

That said - its likely it's not cancer but rather an infection of some sort.

Call the ENTs office - explain how anxious you are. Tell them if there is a cancellation you are willing to drop everything and run in.

Hugs and blessings.