it may not be in your hand. this could be a tattoo created by the graphite that appears like a piece of the pencil. if you did have a foreign body like a piece of the pencil it should have become infected a long time ago. if you did have a retained foreign body the biggest risk would be infection but clearly this has not happened. there would be no health consequences if this black area was just a residual tattoo.
are there health risks if there is a piece of graphite pencil stuck in my hand? . this has been in my hand for the past 10+ years. i'm scared i will have problems in the future but i am not sure what will happen.