The flower essence Crab Apple is an effective remedy for toxicity and infections. It is often used by holistic veterinarians to fight acute or chronic skin problems, such as acne, eczema, mange, etc. The remedy can be given orally in your dog's mouth. (Dosage: 3 to 4 drops 3 times a day).
Another herb that has antibacterial and astringent properties is aloe vera. The gel-like juice soothes the infected skin and helps kill bacteria. Put some aloe vera gel on the affected areas several times a day after washing the dog's face.