Many Chinese medical tourists who go to South Korea for inexpensive and high quality plastic surgery have difficulty re-entering China due to their passports photos not matching their new face post op.
According to Korean sites, some Korean hospitals are now issuing a “plastic surgery certificate” at the request of overseas visitors. Customs officials, of course, are strict about making sure people match the mugs in their passports. These certificates can supposedly help make clearing immigration go smoother so officials don’t have to call hospitals to confirm procedures.
The certificates include the patient’s passport number, the length of their stay, the name and location of the hospital as well as the hospital’s official seal to certify the document. Travellers can show the forms to immigration officials on their return trip home.
This practice of issuing plastic surgery certificates apparently began three years ago, but has increased with the rising number of visitors getting plastic surgery done in South Korea.
(source)