I pop it open, lot of dust around the scroll wheel. So I pop out the scroll wheel, to take a look underneath, sure enough, dust.
I am cleaning it out, when the scroll wheel with it's axle and button fall off the desk, seperating it. I leave them alone, but when I get to the scroll button, a spring pops out. I don't catch where it came out of, and I can't figure out where it might go.
Now the scroll wheel is silent, which is nice, but it doesn't stop rolling, so there's a bit of back and forth motion, like it's loose or like it's a car in neutral.
Dad's gonna notice real quick when he gets home, so I need you to save me! Where do I put the spring?

It's a black Logitech USB optical mouse, with a grey scroll wheel. I can take pictures if needed.