i did the same thing with my insulator mesh melted right into it. honestly i wouldn't put one back in im sure melting plastic is not good to inhale and it will likely melt again.
honestly it works much better without one you can use a thicker wick and get more juice flow,most people just oxidize there wick good and say they have no problems with shorts there,but what i do is use a tiny piece of rolling paper were the insulator tube was i just wrap it around the wick before i slide it in works perfectly and has never burned up on me yet and allows a nice fat wick in there.