You said you were working hard on a project but another lady got the promotion, that’s unfair. A person should get what he has worked for and you have earned that promotion. You shouldn’t leave this matter without speaking against it. It’s wrong that you didn’t get the promotion instead of working so hard. Your boss is on the wrong side and you should voice up against him. I would suggest you to confront your boss and asks for an explanation. You should file a complaint against this discrimination and injustice. It was your right to get a promotion and if you didn’t get that then you have every right to know the reason behind it.