Taking Plan B on my period (and on Birth Control)

Hi so I've been on birth control (the pill, but the highest dosage of progesterone available) and I'm currently on the second day of my period, and he accidentally came in me. He freaked out and gave me the money for a plan B. I feel like it's unnessacary to take it, but I don't want him worried. He's never had a problem pulling out before and I think he just feels really bad about it haha.