In Myeongdong, try Daiso Myeongdong Station (134-1 Toegye-ro) or the flagship

(43 Myeongdong-gil), 10am–10pm. The same line's bubble essence toner (95ml) is ₩5,000 with 21K orders. Under 100ml, so it goes in your 1L liquids bag for carry-on. Cream plus toner covers your hotel routine.