Sorry for the weird picture .. lol

One of my teeth behind lower front has gum recession. I checked all my other teeth and no sign of recession so i don’t believe I have a gun disease right ? I think it would have to effect more than just one tooth ?? If I’m wrong please let me know but I’m gonna call my dentist just wondering if anyone has had this happen and what ended up being the treatment about it. I care about my teeth and the quality of my teeth a lot ! I actually have never had a cavity before in my life and my dentist loves me 🤣❤️ I don’t know what a cavity looks like or feels like so is this what it is ? I have OCD and floss all the time could flossing do this to me ? Could it be caused by my fixed retainer ? I only had it put in last year since my other retainer was not helping my teeth stay straight