He has body dysmorfic disorder. It makes him hate how he looks no matter what he looks like.
I copied this from a website, maybe it will help you understand:
We all at one time or another worry about our appearance, and who doesn't? But when you find yourself waking up and immediately thinking that your nose is too big, your breasts are too small/big, and that your butt is too large while your stomach is not flat enough, and then continuing to have these thoughts all day, that's when there is a problem. Closely linked to other disorders and psychiatric conditions, Body Dysmorfic Disorder, termed shortly BDD, is a serious disorder that estimately affects 1 in 50 people. People that suffer from BDD not only dislike some aspect of how they look, they're preoccupied with it. Most get to the point where it is extremely hard to go outside, meet others, hold a job, and/or feel comfortable just sitting without thinking the self-degrading thoughts. The thoughts soon over-take the victim's mind and it is all he or she can think about. The main core to the problem is the fact that the flaws that the victim has controlling his or her thoughts are all PERCEIVED. Many, many times the defect is imagined, and then blown out of proportion. However, the victim usually thinks, "Well, I can see it so it MUST be real. I'm just not imagining this no matter what anyone says." Victims of BDD, especially in connection with anorexia and bulimia, are usually perfectionists; nothing is good enough either because they cannot see that what they have done is absolutely fine, or because the person has very low self-esteem and cannot believe that someone that is so worthless could actually do something good. So, with the BDD controlling the victim's thoughts along with the inner nature to fix all flaws great or small, you can see and understand why it is so hard for someone suffering from BDD to try and stop their destructive behavior of constantly checking their appearance, and in the cases of someone with anorexia and bulimia, possibly killing themselves