I recommend Yonsei Pediatrics and Adolescent Clinic in Yeonhui-dong.

You know the building with the Burger King at the intersection with the Hana Bank branch in Yeonhui-dong? Since you live in Yeonhui-dong, you probably pass by this place a lot, but I recommend this pediatric clinic. I recently had the privilege of taking care of my niece for a bit, and she wasn't feeling well. ㅜㅜㅜ She had a slight cold, but my sister said it wasn't severe and just had a runny nose, so I didn't think much of it. But after I took her in, she started having a fever and a worsening cold, so I searched nearby and went there. The director is kind and does a great job. Taking children to the hospital and getting them checked out is always a struggle, but she was soothing and patient, which made things a breeze. If you're looking for a pediatric clinic, I highly recommend this one!!