Whitening gel can cause a minor burn on gums. This can make your gums feel tender and create white spots. (The spots will flake away, much like skin does after a sunburn.) The best way to avoid burns is by using professional whitening. We’ll protect your gums during an office treatment. Or we’ll make custom-made trays for you if you choose to whiten at home. The trays help keep gel away from your gums.