Cartilage graft shifted or is it periosteal overgrowth? Small asymmetric bump on bridge after droopy nose rhinoplasty. (photos)

Unfortunately this is not an uncommon residual flaw. You should wait a little longer but I am afraid, it is likely that you will need a revision. You may want to discuss this with your surgeon close to a year from the surgery if you can wait. Your nose bones seem a slightly large but this could be swelling also.

It is hard to predict how scar tissue will develop.  If is bone, then it can be rasped. If it is cartilage it will need to be shaved or trimmed with a knife or scissor..

Skin, bone, and cartilage are all living  and dynamic tissues in the nose. Bone responds to surgery sometimes with an overgrowth or callus formation and additional bone cells being laid down. A minor touchup revision with a rasp can adjust and remove the very slight bump on the main bridge.

Thanks for your post. If you have a fixed irregularity of the nasal dorsum after rhinoplasty, you may have callus formation, bone growth, displaced cartilage graft or scar tissue. If this does not resolve over time, correction is simple but may require rasping/shave or removal of cartilage grafts in this area. Continue to follow up with your surgeon and ask for correction if needed. Best wishes.