Fusible Link, please help

the fuse box has a little blue piece of plastic that helps hold in the wires, when i pull that piece out theres a couple very small marks in it from where something got really hot on it and some black smoke marks and it smells like burnt plastic. The wires are all still connected to it, I dont know if this is normal to happen to the fuse box when something happens like it did to me, the ignition fuse did blow. I just dont want to ruin my brand new wiring harness if its still salvageable.