I am no expert, but I would have to agree that a stray piece of metal in the engine can't be good no matter where it is. I had the same thing happen to me, so don't feel bad. My Dad was helping me, and he had a few nuts in his hand. Next thing I know, he dropped one down one of the holes in the head. I felt horrible mainly because he felt so bad. After wasting two hours not being able to snag it with a magnet, I reluctantly removed the head. I ended up finding it in the head ready to drop in the timing chain cover. In the long run, I am glad I removed the head, because I am not sure what damage it would have done to the timing chain. One of the nicest thing that happened was two different people on the forum offered to drive to my house to help. Is there anyone near you that can help?
Kevin