Discussion: Cupping Therapy is very common in traditional Chinese medicine hospitals, also in many massage places.

I had to cup therapy over one hundred times. (The specialist suggested that it be done after acupuncture.) The suction creates light burns on the skin that have a circular form. It does not have as strong an effect as acupuncture, but I think it may relieve some symptoms, like flu. The spots (light burns) on the body are not equal. Some are red-purple. Others show almost nothing. It is not random and is not explained by the technique.) I believe Cupping Therapy diverts inflammation from other body parts to the skin. (The burns "suck out inflammation.") The main side-effect is occasional inflammation of the burned area.

Link: TCM: Cupping, Scraping, Ginger Therapy, Medicinal Leeches.
https://www.sf-healing.com/page/137 (Copy & Paste)