Broken nose without noticing? (Photo)

Your history suggests that you did break your nose. Bleeding indicates there was enough trauma to tear the lining of your nose. This same trauma could have torn the cartilage and broken the bone. There is no reason to operate on a broken nose unless the cosmetic result is unsatisfactory or there area breathing problems. Many years later you have noticed a cosmetic change. It is unlikely your insurance will cover any surgery to improve your nasal appearance as it is does not affect your health and it occurred so long ago. The surgery involves reshaping the nasal bones and cartilage. It can be done with minimal incisions and in an out patient setting with recovery time in normal social settings of 7-10 days. It will take months to have a final result. I hope that is helpful general information. 

Trauma to the nose can result in a displaced or a non-displaced nasal fracture. Trauma to the nasal bones can cause a callus and a buildup of bone from the trauma itself. To remove the dorsal hump requires a  rhinoplasty. The dorsal hump is composed of both bone and cartilage and must be shaved down in order to remove it. Osteotomies of the nasal bones are then required to straighten the nose bones and reduce the open roof deformity created from the hump removal. For many examples  and more information, please see the link and the video below

Based from your description of the injury, it may, or may not be the cause of the lump but it is most likely that the accident may have cause broken nasal bone or tearing of the cartilage but this may not necessarily have caused the hump because the hump is actually common in your ethnicity. This ca however be readily corrected by rhinoplasty along with other parts of your nose which you want to refine.