Hi there... CTs pick up inflammation, and infection as well.

That said - there was a lot of involvement in your dads nodes, and while it was just his gum area it's possible that it has spread.

Tongue cancer can be aggressive but if caught early enough and treated aggressively it can be cured, I think it has something to do with location, much like base of the tongue and tonsillar cancer.

Gum and cheek can be a bit more jumpy from what I gather. from it's location it can move a little bit around the oral mucosa so it can recur in different locations a bit more easily than the others. Christine has been through it and had a few recurrences.

I am hoping very much that it's not a recurrence, but a biopsy as always is the only way to know. Keeping my fingers crossed for you and your dad.

hugs.