Hole/crater in gums? Anyone wanna help?

I have a crater like kind of hole in my gums, in the bottom front of my mouth, under my bottom left front tooth. It doesn't bleed or anything, and its white, and a tiny bit of the surrounding skin is white. The crater isn't big but its noticeable. It's sore, and hurts when I mess around with it by moving my bottom lip over my teeth. But the pain is bearable, and I haven't tried anything with it. Can anyone tell me what it could be, what it sounds like? Thanks.