What are the chances

What are the chances from getting pregnant while on nexplanon and the guy pulls out every time. So getting pregnant from precum while on nexplanon. I had sex the other day and Before we started having sex I gave my boyfriend a bj. Well I was using my hand and then he gave me a condom to put on him. I never directly touched the tip of his penis with my hand but my hand was on his shaft and I’m just scared that precum had mixed with my saliva and when I rolled the condom up on his penis, I got precum on the outside of the condom. We always use a condom but this time was different. He never came while I was giving a bj so it would have only been precum. I’ve been on the implant for a month now so I should be okay right