My puppy might have gotten a pebble down his ear...HELP??!!?

My puppy was playing in the pebbly area in my backyard and was trying to get my other dog play with him and he rolled on his back. I think he might have gotten a really small pebble down his pointy ears. Every once in a while he will shake his head or scratch that one ear. What should i do? Iam really worried and we cant spen to much on him, no more than $150 or $200.HELP!