Not Skeletor. Google it and you'll see that the character with that name (part of Mattel's Masters of the Universe franchise) looks nothing like this image.
The image in question is the logo of Marvel's "The Punisher."
https://en.wikipedia.org/wiki/Punisher
Variations are sometimes used by members of the U.S. Military in an unofficial capacity. The Army's 24th Infantry Regiment uses a variant called the "Deuce Four Skull," which has the number "24" on the skull's forehead.
https://nothingbutcomics.net/2014/07/22/the-military-skull-art-inspired-by-the-punisher/
Interestingly, that number 2 could potentially form something like a 'question mark' shape on the skull's forehead (much like the 'question mark' shape one might interpret from the photo of BG,) but the colors would have to be inverted (black to white, white to black) in order to make it appear like the shape in the BG photo.
I personally don't think this logo or the "Deuce Four Skull" are actually on BG's shirt, as the logo would have to be placed very high up on the shirt front, very close to the shirt's neckline. (Which is very strange placement, imho.) I'm not convinced that the shape seen is a graphic of any sort (whether on shirt or bandana.) I'm more inclined to think of it as a physical object, like a drawstring or something.
Still, I thought this was an interesting sort of quasi-coincidence.
MOO