fpr seal vanished

[iceburgslim]

Hey guys and gals, I have a question.
I was in the middle of changing the FPR when I went to remove the small O-ring, and it fell down inside the fuel rail.
I installed the new FPR and its seal, planning to remove the fuel rail later when I had time to retrieve the old O-ring.
Without my knowledge, my oldest son tried to start the truck because he didn't know what had happened.
My question is: Could that loose O-ring cause any problems, or would it eventually get pulled through the return line and end up back in the fuel tank?

2000 chevy 1500 5.3