Rasping recovery time. Will the bump will improve with time? Are there other benefits to waiting?

It sounds like you are about to undergo a minor procedure by rasping a small contour irregularity.  Although it is still surgery, the risks are fairly low.  Good luck!

 Rasping down a bony dorsal irregularity is considered a touchup procedure and should take no more than 10 or 15 minutes, as long that is the only thing that needs to be performed. If the bump is large enough, and open roof deformity can be created from filing it down, and then osteotomies are required to close the open roof. The cast will then be applied across the bridge of the nose. It is best to undergo these touchup procedures  under general anesthesia, since it's very painful to try to local anesthesia

A minor revision, such as rasping a small bony irregularity carries few risks.  Timing of the repair is an issue.  It usually takes a full year for the scar tissue under the skin to fully soften.  Adhesions between the periosteum of the bone (the lining) and the skin are common and breaking those adhesions without damaging the skin can be an issue.  The longer wait time for revision diminishes this possible complication.  Regarding the anesthesia, that should not be an issue,