Punishing myself

I was looking at my character sheet the other day and realized that I had made a mistake during the bar fight. I thought my spirit was d8 but it's my smarts that's d8. I was rolling a d8 for becoming unshaken, which was wrong. Because of that, I will be docking myself the xp I got from my bennies last session, since I may not have had them if I hadn't been making that mistake.