Is it permissible to use menstrual blood to treat acne?

It is not permissible to seek medical treatment with menstrual blood, because it is impure (najis). As for smearing the body with impurity, there is a difference of opinion regarding it, but the correct view is that it is permissible out of necessity. However, there is no necessity here, as acne has a cure available through doctors. Menstrual blood is among the filthiest of impurities, and the Prophet, peace and blessings be upon him, forbade seeking treatment with unlawful things.