What is the ruling on performing ghusl after menstruation if there is a wound behind the ear that prevents water from reaching it, and is ghusl valid without washing the ear and the area behind it?

If washing a wound causes harm or delays healing, then one should wipe over it. If wiping over it is harmful, then one should place a bandage over it and wipe over the bandage. It is not permissible to omit washing a part of the body that can be washed without harm. If washing, wiping, or wiping over a bandage is harmful, then one should wash the sound parts of the body and perform tayammum (definition) for the wound.

A wound is either exposed or covered. An exposed wound should be washed; if that is not possible, then wiped over; if that is not possible, then tayammum is performed. A covered wound should only be wiped over; if wiping over it, despite it being covered, is harmful, then one resorts to tayammum.