As we all know, in the past, there was an emperor with absolute authority, the emperor's queen and concubines. Their life together is not smooth, and they must be intrigued and extorted in the harem, so the harem is not so peaceful.
Everyone knows that the emperor's concubines must be well maintained, because they want to stay young forever in front of the emperor, so that the emperor will let her serve more. Otherwise, if it's the other way around, it's just a dying woman waiting for her. Only by staying young can they ensure their status, otherwise it is useless. I know how Empress Dowager Cixi maintained her deep body face to face in the harem. For the first time, she used virgin blood to stay young. This may be feasible at that time, because the technology was not developed at that time, so she must have followed the decision of a quack. Another thing is that she bathes in human milk. She thinks it is beneficial. After all, what the baby eats must be nutritious, so she thinks it is beneficial.
I think there must be more ways for harem concubines to maintain their skin, because there must be other ways. There are too many hospitals in the palace, and those doctors who cure too much will definitely make some lists suitable for them according to their personal conditions, so that's all I know.