The joint looks infected. Possibly from him laying down so much.
You may be able to treat it at home, but if you have vet care, that would be best.
I would give him an antibiotic. Cephalexin would be one of the best choices since this is at the joint, but you could use Amoxicillin.
Clean the wound with Chlorhexidine (Hibiclens) and apply a very thin layer of triple antibiotic ointment. Wrap with vet wrap to help keep it clean. Repeat daily. Keep him on clean dry bedding.
If the joint is damaged from infection and laying down a lot, he may not regain function.
Quality of life and how well he's doing should be accessed daily too.
You may be able to treat it at home, but if you have vet care, that would be best.
I would give him an antibiotic. Cephalexin would be one of the best choices since this is at the joint, but you could use Amoxicillin.
Clean the wound with Chlorhexidine (Hibiclens) and apply a very thin layer of triple antibiotic ointment. Wrap with vet wrap to help keep it clean. Repeat daily. Keep him on clean dry bedding.
If the joint is damaged from infection and laying down a lot, he may not regain function.
Quality of life and how well he's doing should be accessed daily too.