The area around the BB is rock solid. Thanks to our local county a-holes, I came upon a road which was freshly chip sealed, and they hadn't swept yet. A piece of the chip got wedged between my chainring and BB shell and scratched the crap out of my frame. I took it to the LBS I bought my bike and asked if I should worry. He told me that area of the bike is almost indestructible, they've cut up old carbon frames, and they couldn't even smash the BB area. Take that FWIW, but this guy knows what he's talking about, so I wouldn't worry about it. You could tap it with a coin and see if the sound is different around that gouge, and just keep an eye on it. But as-is, you're probably ok.