Looking for great beauty-focused areas in Seoul + good accommodation.

Hi! My name is Aom, and I'm from Thailand. I'm planning a trip to Seoul next month for beauty treatments, as I've heard the city is great for this.

Gangnam and Apgujeong are often mentioned when discussing beauty salons, but I'm not sure which is best for a first-time visitor? Which area is convenient, has natural prices, and good accommodations nearby? I'd like to have time to relax as well, not just be running around all the time.

Regarding accommodations, does anyone have any recommendations for the best time to stay? And does anyone have positive experiences in other areas besides these? I love hearing firsthand stories from people who have been there. Thank you so much! 🙏