I’ve been experiencing a recurring issue for the past few years. There is a specific area in my mouth (near my back tooth) where I get severe, unbearable pain from time to time. Whenever I’ve visited dentists before, they usually told me it’s related to my wisdom tooth and that it would settle on its own in a few days. However, the problem keeps coming back. Right now, the pain has started again and is quite intense. I’m not even able to chew properly. When I checked the area today, I noticed something black near the gum/tooth, which has made me concerned that it might be a cavity or some kind of infection. I'm attaching a photo. Can someone please tell me what could it be? Thank you.