Serious bug... do I need to start all over again?

[harlequ1n]

I posted this in the Mac Support section but might as well do it here also due to the nature of the bug:

I purchased Amnesia yesterday and have been happily playing it in small doses as it freaks me out. But I'm most fearful of having to start from the beginning due to this bug that just happened:

I'm in the Machine Room area, that requires a key to enter to, where you need to insert three rods (which I already did), and in the lower section there's a giant machine where you need to insert 3 missing cogs.

The problem is that I found all the cogs for the puzzle and when I was on my way to inserting the last one, I hit one of the pipes in the corridor leading to it with said cog and it completely disappeared... I've searched the whole level trying to see where it went but my only conclusion is that it got stuck behind some wall or something.

Any solutions before I start over again?