Dog showing discomfort around snout/mouth

My 9 year old Pittbull mix has started yelping and avoiding contact with the front of her mouth and snout for the last day or two. She is making a sound that is clearly distress when even lightly touched in that area, and is avoiding contact if she can. I checked inside her mouth, and while I admit I don't really know what im looking at, her front tooth seems different from the rest. I have a drive link to it, promise its not malware, but can't get reddit to let me attach an image. She generally loves to throw herself at my front door to bark at strangers on the street and I have always been amazed she doesn't get hurt, I am wondering if she finally did.

Tooth Photo
https://drive.google.com/file/d/17DnbMVyxqb1rjOK0JQutb_ZCJV2letln/view?usp=sharing