Annette,
Thanks for your question. The answer is it depends. If the bump if very small then it is possible to just rasp the nose and not “break it”(We call that osteotomies) If however the bump is larger, which is usually the case, then it becomes necessary to perform osteotomies to bring the nasal bones back together. If you can imagine taking the bump off creates a flat top to the nose and as you make the bump smaller the top of the nose gets wider. The osteotomies function to narrow the nasal bridge again and make it round and not flat. I hope this makes sense.
Ed Buckingham