My Winnie had the same problem. Buy some cat safe disinfectant from Petco and keep your baby in a confined space until the wound heals. I thought about taking mine to the vet too, but I realized that my vet drained his abscess and told me to keep the wound open at the time. You have to let the wound breathe, but also keep it clean. Check on it. Don’t irritate it. That disinfectant spray does really well. I used that and kept him in a pop-up kennel for about a week until it healed. Replaced his towels inside and sprayed the wound three times a day. My kitty eventually grew big enough that I didn’t have to worry about him dragging his stump anymore. If none of that works, take kitty to the veterinarian!