Odd stain on edge of molar no visible cavity hole

[Littleteeth]

Hi! I’ve had this tooth that’s been showing gum recession for a few years now since after my braces were removed many years ago. I noticed today that there’s this grey mark on it I dont see a hole and only the gum is sensitive at time if I eat something that bothers the gum. I have good dental hygiene and floss once a day.

It looks like a discoloration or maybe I don’t know. Might this require a filling I’m scared

 

[Gordon]

Looks like some staining from here.

 

[Littleteeth]

@Gordon quick question I went over the grey area with my nail and it felt sensitive like it hurt could that be a stain?

 

[Gordon]

Yes, there's some root surface exposed which can be sensitive to touch. Try massaging some Sensodyne or similar in for a few days. Don't brush with it just rub in with a finger tip. Then leave in place, no spitting or rinsing.