Antonyms for the phrase "do a number on" could include fix, repair, mend, restore, or heal. All of these words carry a positive connotation, instead of the negative or destructive implications of the original phrase. Fixing something suggests a sense of care and attention, while restoring something implies returning it to its original state. Repairing something also indicates a sense of responsibility, rather than the careless disregard suggested by "doing a number on" something. Similarly, "healing" implies compassion and nurturing, which counters the idea of causing harm. By using these antonyms, we can shift our language to reflect a more positive and productive attitude.