Thailand is much cheaper than China for medical proceedures. Hospitals there have more experience, and more ethics. Also, in China there are many unqualified practitioners practicing, especially at the lower end of the market.
Many horror stories about cosmetic surgery that never get published.

Same is true for Dental, ref unqulified practitioners. I was charged top dollar in Shanghai for treatment for tooth ache. I was seen to by one of the partners. Turns out she was no more than a dental hygienist, with a rich dad. She failed to spot I needed a root canal, merely did a deep clean.