Get over it! My dog chipped a tooth also, but I'll never feel like I let her down by not knowing exactly when or where it happened...it just happened. It's not your job to micro-manage your dog's life! That's not what makes a "good" owner good! Good owners care for their dogs, provide them with adequate vaccinations and medical care, and provide them with a stimulating and fun life, and enough training so that they are manageable. Of course you also notice when there are funny white things in their food LOL! You did that, and BB may have more to tell you. But either way, they aren't objects that you control, or live in an environment you can control. They are MAGNIFICENT animals you get the privilege to spend time with. Enjoy that time, it's all too brief. And stop taking things so personally >
PS: every dog I've ever owned loved to ride in the car with the wind in their face. If a dog gets somehow injured by that it's unlucky, but not in any way "your fault". JMHO!
PPS: If it were me, I'd have that spot on her eye looked at by a specialist!