Nothing to do but get that baby to the vet for cleaning, pain control and any stitches and antibiotics needed. They might want to x-ray him and see if part of the bone avulsed off his wrist when the tear happened. The nerves there are extremely sensitive but dogs are stoic - rarely show pain except when it's sudden and acute. Canines are genetically programmed to not show weakness/pain/injury for fear they will be shunned, attacked or left for dead and much of this tendency stays with the domesticated dog. A human with this type of injury would probably be groaning and sitting at the ER right now.
You often have to go into credit card debt for love of your dog but that's part of what we owe them when we take them to live with us. Care Credit may be able to help you avoid paying interest but get that baby seen professionally.
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