My RB Taz had a canine tooth pulled a LONG time ago. I can't remember what triggered the vet visit. I think I noticed him eating funny and his appetite decreased too.

But yes, kitties do not like to show their illness. Taz also had the pseudo cysts around his kidneys and I only knew because his sides had sunk in horribly. He acted just fine.
In fact, he was acting just fine the day I took him in to make the trip to the bridge. But he was very sick.

I hope Cuddles feels all better once her mouth is healed up. Hugs to you and Cuddles!