@ChefShazzy again this is coming from Wikipedia, but I read that there are contradictions in literature on the drug about whether Acetaminophen is a NSAID or not a NSAID, although, the article did mention that if you were going to have to make a choice between Acetaminophen and Aspirin with Crohn's, then Acetaminophen is the safer choice.
@Poofed you can also call your specialist when their offices are open and leave a message with the nurse, the nurse will call you back and be able to tell you what you can take for headache since you have Crohn's. I never ever take pain meds for headaches, I don't get many headaches but when I do I just tough it out.
Also, it is helpful to note that caffeine alone has been shown in studies to increase the effectiveness of pain meds, which could suggest that caffeine has as much to do with headache relief as anything. So, if you can drink coffee without it bothering your Crohn's that might be a way to see if the caffeine alone helps.