Viola is a character who chooses to pose as a man in the play Twelfth Night. She does so in an attempt to woo Olivia for the Duke. Little does she know that she will fall in love with the Duke herself!
Because she chose to pose as a man, she did herself no harm in the long run, no. In the short term, however, she put herself in a very difficult situation because she did not realize she would fall in love with the Duke. Because she had been "hired" to woo Olivia for the Duke, she felt torn. She knew her loyalty was with what she was "hired" to do for him, but she was also conflicted because of her growing feelings for him. Luckily, Olivia had no interest in the Duke and Viola ended up together at the end of the play.
If you would like to say she caused herself much mental and emotional distress, yes, that would be true, but she did no real harm to herself in other ways.