Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin cutis, skin). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs.
When you do a ghusl, you must make sure that there is nothing that would prevent water from getting to your skin.
Unless of course water would harm a particular area and you must keep it dry. In this case, you perform Ghusl Jabirah.
However, if you can get it wet, and you are able to remove the bandage, even though it could be inconvenient or hurt a bit when taking it off, then try to bear it, do the ghusl, and then use a disinfectant and put a new bandage on.
And Allah knows best.
Yes, Diya is obligatory if the beating or hitting caused reddishness in the skin. Diya is to be paid to the person (child) himself either by putting the amount in trust with his guardian or in his account or even by spending it on him.
Any type of deliberate touching between non Mahram male and female is not allowed even with or over cloth.