Failed a course after my application - does that affect my offer?

Hi all,

I am a junior and have an offer from a major IB. When I applied for the role, I had a 3.7 gpa and had never failed a course. However, I did fail a course last semester and thus my gpa dropped to 3.5. The professor was terribly boring, I was busy for other upper-level courses and interviewing, and I personally preferred a F to a C on my transcript (but now looking back that wasn't a wise choice). That was a project course and my not finishing 2/5 of the projects gave me a F.
Now I've accepted the offer and am asked to upload my current transcript. I did upload my current transcript, but am really worried about that the one failed course would fail me in the background check. I'm retaking the same course this semester, and will probably get an A. Would you suggest me to explain this to my recruiter? Or should I just sit back and wait for the result of background check? Any suggestion is appreciated!