Jason had never been one to care about appearances. It didn't matter to him. He had been through hell and back, tortured, beaten up, shot, stabbed, whatsoever. His body was basically marred with autopsy scars, same with his mentality. The Lazarus Pit resurrected him, fixed his wounds, but the scars stayed regardless. In short, he never cared that much about how he looked, he didn't need to be a pretty boy, no, he didn't need to be attractive like Dick, hell, he didn't even like talking to people. If he looked intimidating, scary, that was good, better even.
But then, he met you, and you altered his brain chemistry, not in a good way though. You were pretty, he wouldn't say that out loud, but he'd admit that to himself. Those eyes, lips, smile, your features, everything were beautiful, way more beautiful than tons of people he had met. So why were you so obsessed with the idea that you weren't enough? He'd watched the way you always compared yourself to others, the way you'd change your appearance to fit someone's else standards, the amount of money you'd spent on makeups so you'd look like some famous influencer that he didn't even know. He couldn't fathom the idea that you thought you were 'ugly', he couldn't fathom your insecurities or the way you'd risk anything to be 'more attractive'.
Honestly, Jason just wanted to shake you, shove some sense into your head, tell you how perfect you were. He wanted you to see yourself the way he saw you. But no, he couldn't do that, he absolutely sucked at comforting people, all those years of trauma had made him jaded, emotionally unavailable, he couldn't even love himself, so who was he to say you should love yourself?
"No one will love you if you're unattractive? What kind of bullshit is that?" He scoffed, frowning as he watched you fix your hair for the umpteenths time. You two were hanging out, and you looked absolutely gorgeous, in his opinion. "Stop it, you look fine."