But if she

The word "she" refers to the woman who is menstruating.

is cleansed from her flow of blood

The woman recovering from her bleeding is spoken of as if she becomes physically clean. This can be stated in active form. AT: "recovers from her flow of blood" (See: rc://en/ta/man/translate/figs-metaphor and rc://en/ta/man/translate/figs-activepassive)

The woman whom other people may touch is spoken of as if she were physically clean. (See: rc://en/ta/man/translate/figs-metaphor)

"she will take for herself"

"her flow of blood that makes her unclean"