Wiping over a bandage

As for what concerns a cast on a wound or a fracture;If it is on a wound, the scholars say: the following is to be followed: First: the wound is washed with water.

Second: If touching it harms him,Meaning: he wets his hand and wipes over it.

Third: If wiping harms him, or if something has been wrapped around it, he wipes over this wrapping in both the minor and major states of ritual impurity. Likewise, a plaster on a pain in the back or the neck or the like, he wipes over it in both the minor and major states of ritual impurity.

Fourth: If this is not the case; meaning that the wound is fresh and cannot be wrapped, and cannot be wiped with water, he performs dry ablution with clean earth on its behalf.

So these are ranks: Its washing.
Then its wiping.
Then wiping the wrapping.
Then dry ablution with clean earth.
And this is permissible in the minor state of ritual impurity and in the major state of ritual impurity; because it is a dire necessity, so it is measured by its extent, even if it remains for days or months, the ruling remains in effect; because the ruling is measured by its extent.
And praise be to Allah, Lord of the worlds.
And may Allah send prayers and blessings upon our Prophet Muhammad, and his family and all his Companions.