Is it permissible to wear a wristwatch that has a part plated with gold, and is there a sin incurred for having worn it in the past, and what is the expiation for that?

A gold-plated watch must be removed due to the generality of the evidence prohibiting gold for men, such as the Prophet’s (peace and blessings be upon him) saying: "The wearing of silk and gold is forbidden for the males of my Ummah and is permissible for their females." There is no blame for what has passed after repentance, and no expiation is required.