Hoshi stepped on sandburs today

I was walking Hoshi this morning and he was trailing behind me. When he stops I tug his leash and get him moving again. Well, he stopped behind me so I tugged and he toppled over. That was unusual. Then he stopped again. This time he’s lying on the grass and starts licking his leg. He had a bunch of painful sandburs on his rear paw. I picked them out carefully and checked his other paws. I hate those things. They’re razor sharp.