What really happens when lightning strikes? As Gizmodo notes, our bodies are great conductors of electricity. If you're unlucky enough to catch the tail end of a bolt, you'll likely get a pretty nasty burn at the contact site and at the bolt's exit point — yes, just like a bullet, lightning goes into your body and back out again. Plus, 300kV of electricity will be flowing through your body, so if you happen to be wearing any metal objects or are wet (either with rain or sweat), your wounds will probably be more severe. In addition, the current can wreak havoc on your heart's natural pace, sometimes resulting in arrhythmia or cardiac arrest.
According to IFLScience, Kemp's wounds take the form of a Lichtenberg figure, a phenomenon discovered by German physicist Georg Lichtenberg in 1777. Of course, Lichtenberg's research involved dust settling on electrically charged metal plates, not human flesh — but as IFLScience points out, the high-intensity static electricity of a lightning strike is capable of producing similar patterns in both materials.
Kemp reports that the burns faded within a few weeks, leaving only very faint marks to serve as evidence in what will undoubtedly be a great many retellings of this story to friends, family, and those prized pumpkins.