If the gums are swollen or inflamed, then I would call the Vet and have them take a look to make sure everything is ok. Otherwise, if your furbaby doesn't appear to be in any pain, and the gums are just a little pink, I don't think it's anything to worry about. Normally, the kittens don't even notice it when they are teething. But if they stop eating because of it, it's definitely Vet time.