Hit on tummy tuck scar, left very dark bruise on incision 4 and a half weeks post op. Should I be worried?

Hi,  With you being this far out from your tummy tuck, then the scar is healed very strongly.  It would be very hard for you to hurt it.  Having said that, then it is still tissue that can bruise.  This will not affect your outcome but check with your plastic surgeon to make sure that all is well.  Wait for the bruise to subside but like any bruise, it will take a couple of weeks to do so.  Be kind to the dog !!