I'm going to Seoul for beauty treatments. Where's a good place to go? And where's a good place to stay?

Hi! My name is Bua. This is my first time going to Seoul for beauty and other things, but I'm not sure where to start. 😅 I've heard that Gangnam and Apgujeong are great for people who want to do a lot of beauty treatments, but I don't know the differences between them, and how much time I could save by staying in those areas.

Does anyone have experience? From an overseas traveler like me, could you recommend which area is best and what good accommodations are nearby? I'm planning to stay for about a week, and I want to try many things, but I don't want to travel far to each place. It's tiring! Thanks in advance!