Craig J. Eichler, MD

I suspect the bump could be either a dissolvable suture which was placed superficially or an incompletely removed outside suture.
Since you mention the area is painful I would recommend you return to the physician for reevaluation. Possible suture could be removed.  If it is the absorbable suture it eventually will resolve in time but it could take many weeks or even few months depending on what type of dissolvable suture was used.