Do I need to comply or is my professor just an asshole?

I answered my exams in pencils, because I had no pen. Pencils wasn't exactly off limits as long as your answer was in pen anyways. I didn't have a pen, I asked people around me if they had one but said no extra and the exams started so I couldn't disturb people. I had to finish it. Finished it, asked the professor watching over us if it was okay to submit my paper like this and she said yes. I was relieved. My test score returned and my score was invalid cus my final answer wasn't in pen. So I asked my professor to excuse me, like "hey I didn't have a pen with me so I hope you can understand sir" And he says "when did I ever let u guys use pencils as ur final answers?" I'm aware but like I'm telling u I didn't have a damn pen? The instructor said it was okay?? Like it's MIDTERM EXAMS!! making my score invalid there is like shitty, mind you a lot of students have failed his exams. Still a score of something is better than 0. It's like bro doesn't want anyone to graduate college