Just hypothetically speaking? Or did you DO IT?
You sound like one of those guys who says "ahm, my friend has just caught a sexually transmitted disease. What should I - ahm - he do about it?"
Love it! You "screwed" up!
Sorry, shite-stirring is my life!
Back onto the topic - Is it big enough to get lodged in your fuel line? If it's small enough, it may even go for a wander and you can collect it out of your fuel filter. It's highly unlikely to make that perilous journey tho'.
Eventually it'll corrode and have to come out. Maybe it's a nice surprise for the car's next owner? People have found all manner of things in their fuel tanks, and not had them significantly effect their ride. A little screw shouldn't be a problem.
