I just had the implant put in on Friday, June 24 and today (June 28) me and my SO had unprotected sex. He had came a few hours earlier but didn't finish when we had unprotected sex. Yes, we know to use protection and all of that, we are usually very careful. But I was wondering if I should take plan B, even though he didn't cum. Or if I have nothing to worry about. I know you're supposed to wait to have unprotected sex a week after you get the birth control, but if it sets in within the 3 days that you're supposed to take plan B, wouldn't the implant cancel the pregnancy if there was one?