It’s Brantley Gilbert’s Tattoo!
Brantley Gilbert has at least three tattoos, including this one, which incorporates a skull on his left arm at the elbow. There is also one on his rib cage and another between his shoulder blades. A Google search reveals that he also has a Confederate flag tattoo on his arm, but it's not clear if that is part of the one pictured, or a fourth inking, as there are few pictures on the web. The singer is known to perform without a shirt on occasion; in music and on stage he bares his scars for all to see.