Old Friends Glitches?

[Dollifer]

I've been led to an empty coffin in this quest. I'm sure it's not supposed to be. Maybe I'm being dense but what do I actually have to do? All I can do is open and close it.

 

[Sqeagy]

Is there a heart stone in it?

 

[Dollifer]

Empty apart from a staff of calm which I picked up already.

 

[Dollifer]

The heart stone must have respawned as it was there today when I went to look!

 

[Sqeagy]

awesome!

 

[Friddayy.13]

When I got to the tomb I noticed it had the staff of calm in it too...I grabbed it and went on my merry way without realizing that I wasn't supposed to pick it up. I've already saved it and now I can't go back....am I screwed or can I still fix it somehow?