The phrase "did a number on" is often used to describe a situation where someone has caused damage, harm or put someone in a difficult position. However, there are antonyms to this phrase that can be used to describe a situation where someone has improved or helped someone. Some antonyms include "did wonders for," "put in a good word," "made a positive impact," "put things right," and "restored faith." By using these antonyms, it's possible to shift the focus of a negative situation towards a positive outcome, and highlight the good work that has been done to help someone out.