For example, medical sightseeing can be extended, short-term travel C-32 visa cannot be extended, and you must return to China when it expires. There is no room to talk about it.
Although plastic surgery can't stay in Korea for 30 days, it can be postponed. After all, there is room, which is better than not going back to China at that time. It will be much easier to get a visa. Moreover, applying for a medical sightseeing visa itself is not troublesome. You can search my name directly if you need it.