how can I recover from a huge, fireable mistake?

A reader writes:

Yesterday another coworker and I made a careless mistake that may have huge results. Among other things, our company may lose a contract because of our error. Our mistake was probably a fireable offense and certainly one that merits being written up. I think the only reason neither of those things has happened (yet…) is because we have both been stellar employees otherwise. I’ve made smaller mistakes here and there during my two years at this job (basically the ones everyone makes) but never one with such big consequences.

I had my annual review two weeks ago with my supervisor and it was nothing but praise and an unexpectedly large salary bump. Among other things, I was told that I’m very consistent and dependable. I’m devastated and disappointed in myself for proving otherwise. How can I recover from this mistake and make my supervisor think of me as a great employee again?

I answer this question over at Inc. today, where I’m revisiting letters that have been buried in the archives here from years ago (and sometimes updating/expanding my answers to them). You can read it here.

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