A veterinarian or naturopath who sees animals could be helpful in determining what is causing the spots and tags on your dog's skin.
Some oils that are generally supportive of the skin are:
Lavender - Lavender helps keep the skin clean, while it reduces swelling, and promotes the growth of new, healthy skin cells.
Chamomile (German or Roman)- also provides relief from swelling, pain relief, as well as promotes skin regeneration. Considered one of the gentlest oils.
Geranium - Used in the treatment of wounds, bruises, psoriasis, eczema, and acne, Geranium is a broad-spectrum oil for skin care. It is also is an insect repellent, in case bug bites are a problem. While it is non-toxic and non-sensitizing, some hypersensitive individuals may experience irritation.
All of these oils are non-toxic, non-irritant, and non-sensitizing. All of Ananda's oils are therapeutic grade, such that even if your dog ingests the oils, it won't harm him.
Try this recipe:
1 ml Lavender
2 ml Chamomile
1 ml Geranium
2 oz. Sweet Almond Oil
Use a few drops at a time as a spot treatment. Start with once a day, and if no irritation appears, up the dosage to twice a day.
Best of luck to you and your Pup!