Thank you, ***** ***** like it is either infected or he has possibly fractured his toe and is licking the skin too much because of the pain.
So the way we determine if it is an infection or a fracture is to take an x-ray.
If it is infected he will need oral antibiotics.
If it is fractured it would be splinted for 4-6 weeks.
I would try to get him into the vet tomorrow. Since it has been going on a number of days it is probably not an emergency at this point.
If you go to a large pet store like Petsmart you can buy a plastic e-collar to stop him from licking the toe and causing further damage. Make sure the e-collar extends past the tip of his nose or he will still be able to reach his foot if it is a front leg.
For pain you can give him human aspirin. 5 mg of aspirin, per each pound of puppy, every 12 hours as needed. Give it with a meal to help prevent gastrointestinal upset.
You can apply over the counter neosporin to any areas where the skin has worn off three times a day.
You can also do warm water epsom salt soaks. Put a cup of epsom salt into 10 cups of warm water. Soak the toe for 15 minutes twice a day.
How does that sound? Do you have any additional questions?