What does scrapping mean?

Rash is the external reaction of pathogenic factors in the body on the skin. We can judge the physical condition by the reaction after scraping. For example, the red color of the image represents heat or inflammation, and the purple color of the image represents stagnation of meridians. For example, the image is purple-black or cyan-black, with a large area and a lump, indicating that the body is sub-healthy.