First, they see what kind of problem the dog has in it's leg. Then, if it's really bad they may need surgery. If it's a mild ingury the dog just may need to give it some time to heal.
Take it to the doctor... it may be something serious... my dog tore his ACL and he needed surgery... it may be that your dog tore his ACL and needs surgery... Please don't let your dog be in pain any...
Do you know why they are hurting, accident etc. I need age of dog to help you, could be due to arthritus or other illness, do not give human medications, there are inexpensive ones you can get a your...
Never try and self-medicate the dog. The best thing to do is to take it to the vets immediately. In the mean time, try and keep the dog still as to limit any more damage to the leg. If it is...