I'm finally going to Seoul! Please recommend must-try beauty treatments and skincare spots~

To all my sisters, I'm flying to Seoul next month and I'm super excited! I've always been really interested in Korean skincare and beauty treatments, and now I finally have the chance to experience them. I've heard that Seoul has many different beauty districts, like Gangnam and Myeongdong, but I'm not sure where to start.

I wanted to ask everyone, do you have any must-try beauty experiences when you go to Seoul? Like skincare management, facial treatments, etc.? My skin is a bit sensitive, so I'm looking for treatments that are gentle but effective. Also, are there any things I should be aware of when trying these out there? It's my first time, so I'm a little nervous but also very much looking forward to it.

If you have any personal experiences you'd like to share, or know any areas that are particularly worth exploring, please let me know! I have a budget in mind, but I'd also like to get an idea of the general price range. Thanks, everyone!