Bone or tooth fragment?

[wisdomtoothremoved]

I've had my upper wisdom tooth removed almost 3 days ago. I recently noticed a small and hard piece connected to the adjacent tooth. Is this a tooth or a bone fragment and is it normal? It also hurts quite a bit.

 

[MattKW]

Can't tell from your photo. Usually bone that works its way out. Go back to dentist and have it removed.