Antonyms for the phrase "becomes worse" could be "improves," "gets better," or "progresses." When something "improves," it means that it is becoming better or showing progress. Similarly, when something "gets better," it means that it is advancing towards a better state or condition. Finally, when something "progresses," it means that it is moving forward and developing in a positive manner. These words are useful to describe the opposite of "becomes worse" because they convey a sense of positivity and improvement rather than negativity and decline.