Plan B

So me and my boyfriend just made love and he came inside me because I said so and we both planned on doing it. But ofc he’s going to buy me a plan B tomorrow. Just to make sure it is going to work right ? Idk why I’m asking even though I took it once but he didn’t came in me but now he did but it’s going to work right because you can take it up to three days of having unprotected sex. I just want hear you guys comments. Thanks :) no hate plz :/