WHAT IS GUA SHA?
Gua Sha (“Skin-scraping”) is a technique that intentionally raises skin rashes. ‘Gua’ means to scrape or rub. The area to be rubbed is lubricated with oil. In Gua Sha stimulation, the skin is pressured with strokes by a round-edged instrument this results in the appearance of small red petechiae called ‘Sha’, which fade within 2 to 3 days and can be tender while healing. The skin is then rubbed with a round-edged instrument in strokes. One area is stroked until the rashes that surfaces is completely raised.
Gua Sha is a technique that has been used in traditional East Asian Medicine for thousands of years. It is also known as scraping, or coining, because in ancient times coins were used as the tool to rub or scrape the skin. People growing up in a traditional Asian family often recall a grandparent using this technique to help resolve fevers. In modern day there are very expensive tools and techniques (such as Graston ®), they have based their therapies on Gua Sha. Some physiotherapists use a version of the technique known as Instrument Assisted Soft Tissue Mobilization (IASTM). By using a tool instead of the hands during a massage allows a physical therapist to apply more pressure.
HOW IT WORKS
Gua Sha promotes normalizes metabolic processes and circulation to the muscles, tissues, and organs directly corresponding to the area treated, and facilitates metabolic waste carried away. Small injuries to the body, such as the Sha caused by Gua Sha, can be described as microtrauma. This microtrauma creates a response in the body that may help to break up scar tissue and remove cellular debris stuck in the tissue. Microtrauma may also help with fibrosis, which is a buildup of too much connective tissue.
BENEFITS OF GUA SHA
Gua Sha is often used to treat muscle pain and tension, but until recently there has been limited research into how well it works. Clinically the most common conditions treated by Gua Sha are of the muscles and bones, known as musculoskeletal disorders. Practitioners may use Gua Sha on connective tissue that is not working to move joints as it should. Some examples include back pain, neck strain, elbow pain, foot pain, tendonitis and repetitive stress injuries.
A 2014 study found that Gua Sha improved the range of movement and reduced pain in people who used computers frequently compared with a control group that had no treatment. 
In a 2017 study, weightlifters who had Gua Sha felt that lifting weights took less effort after treatment. This could suggest that the treatment speeds up muscle recovery. 
Older adults with back pain were treated with either Gua Sha or a hot pack. Both treatments relieved symptoms equally well, but the effects of Gua Sha lasted longer. 
After a week, those who had received Gua Sha treatment reported greater flexibility and less back pain than the other group.