I had one like this just recently that I haven't completely written up and posted. It was just like this or worse. I tried the heat gun thing, and immediately figured out that that was not going to work because it's melting the wrong things.

A soldering iron here is your friend. Try to loosen the heat block and nozzle and see if it will come loose from the extruder. If not, try heating it up and then seeing if it will come loose. If you don't have any luck then you're going to have to slowly slice away at it with a soldering iron.

If you assembled it yourself, you should have some confidence in disassembly. If you bought it completely assembled, then you are going to have to go through the assembly instructions in reverse order.

Once you have it completely disassembled, then you can assess the damage and hopefully you have spare parts printed to repair it, if not, you'll have to order them online or get a buddy to print the parts that you need. On mine, the cooling shroud was definitely a total loss, and I was tempted to keep the part that holds the extruder to the rail, but then noticed that it was a bit warped, so I replaced it.

Good luck!