Epson salt soak, clear iodine, and triple antibiotic cream without pain relief. You want to start with a soak in the salts for at least 15 minutes. Then apply the iodine, let dry. The apply the antibiotic cream and wrap the feet. Keep the duck on clean dry bedding until you can get the bumble out and healed.
I know you have to remove it but I don’t know enough to talk you through that part.