The OP didn't specify whether he was using Windows or Mac OS.
"Computer Management" sounds like Windows to me, and one should unmount a USB thumb drive from Mac OS, too. While I have never run into a case of data corruption from failing to unmount a thumb drive properly, that it is possible seems to be the conventional wisdom.
I assume data corruption is most probable if the drive is pulled while it is being written to
. Since the OP pulled the drive while it was, perhaps, still reading, the drive may work again if the computer is rebooted. (It's amazing how many things will simply work again on a Windows computer after a reboot.)
If a reboot does not fix the problem, the OP might check out the volume recovery apps written specially for flash media.