Belly button piercing rejecting?

i got my belly button pierced two weeks ago. the piercer did a great job and i am not in any pain. there are no signs of infection at all, but i do have this bad habit of sleeping on my stomach. when he pierced me, he pierced form top to bottom and so my top hole was a little bigger and more irritated at first. when i got up a few days ago i noticed that the top ball of my jewelry was kind of sunken into my skin. i used to bottom half of the piercing and pushed the top ball up and cleaned under it. there is now an indentation of where the ball rests normally but there is almost no skin there but it is mostly exposed tissue. again im felling no pain or irritation out of this. im going to see the piercer tomorrow to have it checked out. could i possibly be rejecting or is this because of my bad sleeping habit?