Mark found mark

My instructor Mark from a year ago found my final exam!  He gave me a zero for the final in his steel construction class because he could not find it.  Long story short – I put my work in one pile and the exam paper in the other on his desk.  I asked, and he looked twice before, but he said he couldn’t find it.  Finally, a few days ago, I asked him if taking his current class will erase my old mark.  He said it wouldn’t but that he’d look again for it.  “I remember now that you took the exam with the other section group,” he said, and that he’d look for the exam again.  He found it, graded it, and submitted the grade and documentation to the registrar’s office.  I’m waiting to hear back to confirm that my mark has changed.  I will get a B- in that class.