Assuming you don't have any other medical conditions such as diabetes a bruise normally heals and goes away on it's own within 15 days.
Once you get a bruise there's not much you can do to make the bruise go away except just give the bruise time for it to heal.
You could apply some ice to help with the bruise but it won't fully go away or you could cover the bruise up with some concealer or other makeup.