I recently got my teeth cleaned with a water jet type cleaning by a new hygienist. A few days later, my bottom front gums felt irritated. I took a look, and one gum looked as if it had been cut down toward the root about 3 mm below the normal gum line, like it was a mistake. I used a peroxide-type mouthwash and declined follow-up visits to the same dentist because I did not trust the experience of the hygienist. Ever since, I have been trying to treat the gums and also noticed an odor and greying area toward the root, and it has become difficult to manage the irritation. It also looks like a cavity may be present. I have attached a picture.