In Myeongdong, Olive Young Myeongdong Town (53 Myeongdong-gil, 1F-2F) and

Central Myeongdong Town (M Plaza, 27 Myeongdong 8-gil, B1-3F) are close, open until 10:30 pm. For use on the trip, the 50ml mini (1.3K+ reviews) is handy and fits your carry-on liquids bag.