@Finalbeta This is when Marco gets hit by two casual lasers from Kizaru :
(He didn't even bother to shoot at his head lol)
In the next chapter, he is still losing blood and he is shown regenerating. By the time he gets handcuffed (preventing his regeneration powers from working further), he was still showing damage.
This was Kizaru in trolling mode. When he fired the Yakasani, Marco had holes even in his eye. Had someone else been hit by that and that did not have the luxury of regeneration, things would have been real ugly.