If your plug shot out then it probably stripped the threads in the head. You'll need a helicoil to fix it. It's a fairly common problem actually.
I had something similar happen in the middle of a road trip, but thankfully, the plug actually failed. The center porcelin part shot out of the threaded portion.
The fig newton is a bit of a joke. The center electrode of the plug had stayed behind. Stuck between the 'nut' of the plug and the sidewall of the hole. It's not magnetic & I couldn't get it out. I told my wife I need gum or grease of some sort to stick on the end of a screw driver. She suggested the fig newton. Worked beautifully. Now anytime *anything* needs fixing, she asks if a figgy will help?