
Generally, a topical treatment is used to treat acne. Some are similar to the ones people use, like benzoyl peroxide. Use only the products recommended by your veterinarian. The skin on the chin and lips of your dog is thin and sensitive. Therefore, if benzoyl peroxide is prescribed, it is much weaker than that used for humans, so do not substitute.
Some possible treatments:
Protect your animal from injurious situations. Also, try to limit your pet's activities during this time. Remember, this ailment is self-limiting and will not last very long. You will need to manage the condition at home, shampooing as necessary and applying the topical medications.