Sometimes, human doctors can be persuaded to help, if they are animal lovers. Possibly could put in a call to an animal clinic that can give information regarding pain medication and dosage requirements. Just a thought. When Corky was 9-10 months old, he jumped from my mom's arms and broke both bones in his front leg. I'll never forget his screaming & crying in pain. It was a Sunday night. The emergency clinic wrapped the leg to stabilize it and gave him an injection for pain and additional pills to keep him comfortable through the night. In the morning, we took him to our regular vet where they did surgery to insert a pin and to put a regular cast on his leg. Because he was still growing, they put him under anesthia twice during the next 8 weeks to Xray and change his cast. Today, 3 yrs later, he doesn't have even a limp. Dogs and cats are remarkable in how rapidly they recover and adapt. I hope this information will help somewhat. Wishing the best for your kitten.
When I was young, I admired clever people. Now that I am old, I admire kind people. -Abraham Joshua Heschel, theology professor (1907-1972)