Have your dog lay down on his back on your lap. Relax him, and slowly massage his extremities. Use your thumb and your index fingers to feel the joints of the foot that got hurt and compare it to the one that is normal. Sometimes, all it takes is the joint snapped out of it socket. Used Chinese Ointment (liquid tiger balm) or BenGay to massage the hurted foot 4-6 times a day. Do not let your dog run or walk too much. Please carry him outside for potty. This happened to my little LuLu. I was frustrated for a week, and someone on this website recommended X-Ray & Surgery. What you need to do is watch how he walks and how he put his foot down to the ground. Your baby will tell you.