Is it harmful to forget to bring facial cleanser when staying in a hotel, and to wash your face with clear water all night after applying isolation foundation?

Only occasionally, it doesn't hurt too much. As long as you don't forget to remove makeup for a long time, there is not much cosmetic residue.

Hotels (also known as hotels, hotels, inns, guest houses, business trips, inns, hotels in China, and hotels in Malaysia and Singapore) are basically defined as business organizations that provide safe and comfortable spaces for users to have a short rest or sleep. Generally speaking, it is a place for guests to stay and eat. Specifically, a hotel is an organization that provides services to its guests through the sale of rooms, restaurants and comprehensive service facilities, taking its buildings as evidence, so as to obtain economic benefits. The hotel mainly provides accommodation services, living services and facilities (bedtime services), catering, games, entertainment, shopping, business centers, banquets and conferences for tourists.