Uh... I'm not certain what you're telling me, but what I meant to say was that it's not a tattoo under his eye, it's a drop of sweat... sorry if I confused you. It seemed like you were asking about why he had this"tattoo" but it's actually a sweatdrop. It's because he's flummoxed.
Okay, I see where you are coming from now. Because to me it looks like a tattoo symbolizing people killed, much in the same manner airplanes and jets receive marks for enemies shot down by the pilot. A person who has killed multiple times will have multiple marks, looking like 'tears' on their face. My initial question wondered why this character, who before lacked the spine, would be marked in this fashion. His depiction is hardly athletic, let alone shown with any skill in a fight, and is usually the one getting owned if there is violence. Did he just get lucky in a fight with an inmate? Or was he blamed for life he didn't end?
To be honest I haven't paid attention to this artist's depiction of perspiration or precipitation, even though he has depicted both characters working out, and standing in the rain. It just struck me that the sweat-drop/tear was right where I normally see such a tattoo, I was wondering how he had killed someone.
Oh! Well the vast majority of people don't jump to that conclusion, but I see where you're coming from. I never had that knowledge so I wouldn't know this. I just know from other works of art that this is a general way of depicting a drop of sweat in a cartoon work. We both learned something new!