I discussed this w/ @wicked-felina​ who says:

Hmm. Louis would probably believe criticism of his looks (I like the headcanon of various people, including @gairid​) that he felt different and weird because of his androgynous beauty as a mortal. But he would protest that he doesn’t care about his looks

There was also a headcanon (@gairid‘s?) that his mother found his eye color strange and ruthlessly criticized him over that and other things about his appearance. Maybe that’s why Louis retreated into art and fiction for his aesthetic tastes, that the ideal of beauty captured by artists and writers was superior to what reality could offer, including his own appearance. The fact that he ran the family business and provided for his mother despite her attitude towards him taught him that actions, things you can change, have more weight than something you’re born with and cannot change, like your eye color. 

I headcanon that Claudia playfully called him ugly on more than one occasion, and called him ugly on some not-so-playful occasions later on, too. Only someone he loved that much could wound him like she did about that subject.

Louis probably still has a lingering feeling from his mortal days about his looks, but if confronted about it, would probably roll his eyes and change the subject.