Does impurity transfer from the bottom of the shoe to its top, and then to the foot, if one walks on impure areas? And is the entire body considered impure if menstrual blood comes into contact with water on a completely wet body?

The cure for obsessions (waswas) is to ignore them and not pay attention to them. Impurity is not judged to have transferred merely by doubt. The imagination of impurity transferring to the foot from walking on ground that became impure by a wet sandal is a baseless obsession (waswasa). Some scholars have opined that impurity does not transfer from an impure object to a pure object if one of them is wet, and this opinion can be acted upon by someone afflicted with obsessions. The impurity of menstrual blood does not transfer to any part of the body merely because it is wet; only the point of contact becomes impure, and a small amount of blood is excused. The matter is easy and only requires resisting obsessions and ignoring them.