I'm up to some bit in a prison where you weaken a lock with acid and  break it which SHOULD open the door. As soon as I used the acid and hammer combo a monster appeared and kicked my ass but only because the DAMN DOOR didn't actually open. I thought I did something wrong so I after a few more tries I went to a walkthrough which told me to do exactly what I did. So wtf? Is the door jamming a bug? Its not like I can revert to an older save can I? I can't even leave the area. Also the glass jar used to hold the acid won't hold acid anymore. This is kinda pissing me off. If anyone knows what to do their help would be very appreciated. To be a bit more specific, I'm in chapter 14 of this guide. 
http://www.gamefaqs.com/pc/978772-amnesia-the-dark-descent/faqs/60857

There is a known acid jar bug, you may have to hack your save file. There is some info on this over at the Frictional games forum. BTW, it's not hard messing around with a save file, as all inventory data is stored in an easy to edit format.
Also, you can revert to an older save. Go to the main menu and there should be an option to load a file.