With any acute trauma like you describe, it’s best that your dog is examined by a veterinarian so the most appropriate treatment can be recommended.
When there is a paw pad laceration to the point where the pad appears to be ripped off, there are concerns for inflammation, pain and infection.
The paw is a dirty place, as is the ground, so there are a variety of microorganisms (mostly bacteria) that can get into the skin, connective tissues, bloodstream and lymphatic vessels.
Your Pug’s paw will need careful flushing (with or without sedation/anesthesia) to remove debris, and the lacerated piece of paw pad may need to be surgically removed.
For home care, you’ll need to clean his foot using antiseptic solutions or wipes, along with (likely) giving him oral antibiotics. His foot may need to be bandaged (pending your vet’s evaluation) to prevent further trauma.
As the injury site will also be painful, some form of pain-relieving medication (anti-inflammatory, opiate, etc.) should also be used.
Rechecking the injury is also very important, so make sure that you schedule a few follow-up appointments as per your veterinarian’s recommendation.
Dr. Patrick Mahaney