Okay--in the interests of full disclosure I have to tell you I'm a prof at a university in the behavioral sciences and the medical note is probably not going to fool your prof. In fact, I don't even accept them anymore for makeups, unless it's a hospital stay. You may think your prof is not going to notice that you're underperforming, but he/she knows all too well that you just fell behind and now are trying to salvage the situation. I don't know what time it is where you are--where I am it's late afternoon, so you may have already blown off the exam. In my opinion, you should have shown up, owned up to it, which would have made you look less immature to your prof, and asked honestly if you could have a makeup. If I were your prof, I would have respected you more for being forthcoming. (I probably still wouldn't have given you the option to make it up, though!)