I recommend The Return Dermatology Clinic in Bongmyeong-dong, Daejeon.

I went to this place a while ago, and it was surprisingly good. They also gave me thorough skin care advice, so I highly recommend it. There are both female and male directors. I met the male director, and he immediately told me to get a facial mask. I was skeptical, but I got it. My skin felt incredibly firm!