Muslim men cannot wear bracelets, whether they are of the type mentioned in the question or other types, and whether they are made of leather, metal or anything else.

There is nothing wrong with changing the colour of the skin from dark to white, using creams, cosmetic preparations and the like, if the change is temporary. But if it is changing the colour of the skin permanently, then it is not permissible.

The `awrah of a man is the area between the navel and the knee; as for the navel and the knee themselves, they are not part of the `awrah.