Which area would be most convenient for me to stay in Seoul for my first beauty treatment?

Hi everyone! I'm Wen, and I'm planning a trip to Seoul next month to try out some cosmetic procedures, but I don't really know much about the area. I've heard there are many cosmetic clinics in Gangnam and Apgujeong, but I'm not sure if that's true. Has anyone stayed in these areas? Are they really as concentrated as rumored?

My biggest concern is accommodation—I'd like to find a place that's close to a cosmetic clinic but also convenient for shopping and dining. Are there many hotels and guesthouses in Gangnam? Is transportation convenient? Or are other areas also good? I'd love to hear your real experiences, especially advice from friends from China!

Also, is there anything I need to prepare beforehand? Like a passport, insurance, etc.? Looking forward to your sharing!