I’m nervous

So I had sex with my boyfriend and we used a condom. But, before we had sex I was giving him a quick blow job and was using my hand a little bit. I’m worried that some precum could have mixed with my spit and got on my hand and then transferred to the condom when I put it on him. He never came while I was giving him a blow job but I’m scared of precum containing sperm and transferring from my hand to the condom, We we’re just messing around for a second before we had sex. I also have the nexplanon implant but I’m just scared it might not work, that’s why we use the condoms. I’ve only had it for a month. Should I take a plan b or would you guys be worrying? Is it possible that precum sperm could have transferrred to my hand to the out side of the condom?