If this is a front-mounted USB on a desktop or tower, it probably connects to the motherboard with (about) 4 small wires. I'd unplug it, consider it damaged and unusable, plug a small USB hub into the back (where it will probably have more USB sockets. Make a note of the colour sequence of any wires you unplug in case you manage to get a replacement (they usually seem to come with cases)
It may still be possible to buy a PCI card or similar that adds USBs, but most modern PCs come with plenty, and you only need one working one to plug in a hub that will give you another 4 or so.