What is the meaning of a skull tattoo with the lightning bolt goinng through it?

No particular meaning, unless it is based off of some military emblem, as some factions have had in the past incorporated skulls. BUT, with that said...to the right set of eyes, this could be construed as a white power tattoo. The reason for this is primarily the "Death's Head Skull", which was the emblem for the SS (Adolf Hitler's secret police), as well as the SS Bolts, which is quite simply two black bolts side by side. So...the bolts with the skull could make someone conclude that the wearer is a racist.