We live in Northern Illinois. Five or six years ago we had the roof replaced on our detached, single family house. The job seemed to be well done and we had no complaints. This afternoon, however, as I lay down on my bed for a moment, and, looking straight up, noticed a nail protruding through the white, finished ceiling directly above me. I look at that spot in the ceiling multiple times a day, and there is no way that the nail was protruding before this afternoon. The house has two stories, and a 16 foot ceiling in that room. No one, to my knowledge has been on that part of the roof since the new roof was put on.
So, is it normal for a nail to come through so long after the new roof was put on? In any case, what dangers/issues are there with this situation, and what steps might I take to correct the problem? Picture attached.