The correct name is Huang Lian in Chinese and Coptis Powder in English. It is one of the most bitter non-toxic nutritive substance's known.
Online, most of the Coptis supplement's available are in teapill form which is not powdered. You could use the capsule form if available and open the capsules to apply Coptis topically.
If you have difficulty finding it online please have your veterinarian order it for you from Dr. Xie's Jing Tang Herbal Company (google it online). Jing Tang Herbal only sells to veterinarians with a prescription.
Your dog may also benefit from the product: Four Paws Damp Heat, also available from Jing Tang Herbal Company. And no, I am not affiliated with this company.
Hi,
I have called around to friends in the area that use homeopathic products and no one has seen this particular herb. I wish I could have been of more help. Keeping the hot spot clipped and clean to allow the air to get to the lesion will help the healing process.
Good luck finding the herb.