My mother in law just bought me this as a shower replacement and shampoo replacement for confinement. Has anyone ever used this before? It's from Hong Kong

Not showering during confinement is a myth in Singapore's context (also acknowledged by Eu Yan Sang https://www.euyansang.com.sg/en/beware-these-6-confinement-myths/eysfertility1.html). Keeping basic hygiene is important, especially since you will be handling a newborn in close contact. Bathing with warm water is sufficient for keeping the "wind" out of your body, if that is what your MIL is concerned about. Blow drying your hair after a shower probably helps too. Caring for a newborn can really work up a sweat, so please do keep clean and hygienic for the sake of your baby!