Hi welcome to Health care magic forum.
Thanks for choosing H.C.M.Forum.
You have scrubbed the road, while saving your dog from other dog. You have swelling and pain and difficulty in walking.
There are 2 possibilities, 1 is abrasion of the skin.
2nd is fracture
of the metatarsals, or phalanges. These wont restrict the movements, but will cause pain and swelling.
I advise you to consult an orthopedic surgeon for diagnosis and treatment. You may need to have an X ray
besides other routine tests for confirmation or exclude the fractures
Wishing for a quick and complete recovery.