that happened to me as well. gargle with salt water as often as you can. i cannot remember much, but i do think i got it out. relax. if it does not come out, it will be covered in skin to contain it. your body will either get rid of it, or do it's best to keep if from moving.
hm. Well, I hope you didn't swallow a toothbrush bristle. Truth is, it probably would wash down. They aren't really that sharp to dart into the side of your esophagus. But it may have irritated it on the way down. Gargle with salt water. Drink lots of fluids. You can try one of the throat sprays that numb the area. But this should be getting better.