Happened to me on my modern physics final. I was a good student so the prof grilled me for an hour, make me do some sample problems of the board in his office and finnaly said “you know rthis stuff” and gave me an A.
My daughter missed one of her exams last week. She went to the professor’s office. He looked at her attendance record, saw that she hadn’t missed a class, and allowed her to take the exam in his office.
Good luck to you!
Oy, does this bring up a bad memory for me. I missed the last day of class (out sick), but knew when the final was, studied for it, felt really good about it and showed up twenty minutes early to take it. Strangely, no one else was there yet, but whatever. Fifteen minutes to go, ten minutes, five minutes, it’s now test time and still absolutely no one else has shown up and I am straight up freaking the hell out. I go over to the professor’s office, only to find out that I have missed the final by two days! The secretary calls the professor… and he tells her, hey no problem, there’s a copy of the final in my desk, have him take it in an empty room somewhere. I aced the exam, and got an A in the class.
Fast forward a week (after spring break) and I show up to my first class of the new quarter with, oh, probably fifteen people from the previous class. “Dude, what happened?” Me - “HOW COME NONE OF YOU BASTARDS BOTHERED TO CALL ME AND ASK WHERE I WAS?!?”
I had a near miss like this once. Freshman year, I had two final exams on the same day. For the second exam, which was in my strongest subject of the semester, we were allowed to bring one page of formulas. My plan was to get a good night’s sleep, eat a hearty breakfast in the dining hall, take the first exam, whip up my note sheet, then go take the second exam.
As I entered the dining hall that morning, I saw a bunch of my classmates sitting together. I joined them, and naturally the topic of conversation was the upcoming exams. As we were leaving, someone said something that made me realize I had the order of the exams mixed up. The one with the formula sheet that I hadn’t written was right now.
10-question exam, and I left the last 3 blank because I just had no idea what to do. I didn’t sit around wracking my brain and hating myself; I read the questions a few times, acknowledged that I was clueless, and turned in the exam an hour early. Thankfully the professor had given so much extra credit during the semester that I still got an A in the course.
I’m planning on having a giant calendar with test dates and such written prominently on it for next semester. Also, multiple reminders on multiple devices.
It happened to me, thought the morning exam was in the afternoon. Regulations required an automatic failure. But it helps to be the top student in the class. The professor said, “Forget it” and gave my my A anyway. Phew! That was around 55 years ago.
I’ve actually done this twice. Once, in high school, me AND two friends (who went to a different high school) all got the date of our Chemistry Regents Exam [statewide subject test]. Getting to the testing site and realizing Something is Wrong is definitely one of the worst feelings out there. Without passing this exam, I couldn’t graduate from high school, but my score didn’t affect my class grade. I was able to sit for the next scheduled exam at the end of the summer at no penalty. Whew.
I also once missed a Calculus final in college by getting the date wrong. I had actually been doing very well in the class. I was not allowed to take the exam or a makeup. In the end I passed with a C- based on my 2 previous exams and class participation. I had been on my way to a strong A before this, but I was bracing for a D so I was basically thrilled with any flavor of C.
Pretty much exactly this happened to me. I decided to ditch my philosophy class–the first time I’d ever decided to skip a class, first semester of freshman year–to study for a physics test later that day. Somehow I spaced out that there was a phil exam that day. I had actually emailed my phil prof the night before to let him know I wouldn’t be attending (it was a small class). I got an email back that morning saying, “You know we have an exam today, right?” HOOOOOOSHIT. Cried my eyes out the whole time, biked like a madwoman, and arrived just as he was closing the door with a box of blue books under his arm.
He was so nice about it. He said if that was the biggest mistake I ever made in my academic career, I’d be just fine. And let me retake it during his office hours the next day. 
I actually emailed him about 5 years after that incident happened to thank him, haha.
I had a final; I thought it was Thursday but it was actually Tuesday. Got to Wednesday before I even realized I missed it. Had otherwise good grades and the prof let me take it later. Got an A, IIRC.
Another time, the *prof *forgot which day the final was on. Eventually someone got through to him and he showed up a couple of hours late. I was glad I didn’t have any other finals immediately afterward.