Today, I discovered a pretty substantial fuck-up in something I did at work. Not a lose-your-job fuck-up or anything, but still embarrassing. The worst part is that it happened because I wasn't properly trained on something when I started and I was told (by my boss) to use information for this project that turned out to be faulty. I'm going to have to tell my boss about it, and that's going to blow, because it's going to look bad for me if I don't explain what happened, but the truth is that this happened because of things that were beyond my control (and partially caused by him). That means I could be perceived as not owning up to my mistake and trying to blame my boss for it.
Not sure how I'm going to deal with this one.