Overly concerned about appearance

This is an issue that impacts my relationships with others. For context: when I was a child I was bullied very often and I was told it was because I'm ugly. I also had a skin condition which has healed. I am not ugly. At worst I am average, and when I dress myself up I look nice. I have a very attractive partner and he finds me attractive. My friends and family and even strangers tell me I am pretty. But unless I put on makeup and dress my best I feel like it's a lie. The only reason the bullies stopped being mean to me was because I learned how to dress myself and I went through puberty. This gave me confidence which scared them. I am concerned about how I look to the point that I might appear vain but honestly I just do this because it makes my life so much easier. People are nicer to me when I dress up. I get more opportunities and better treatment. My partner and my family are the only ones who I believe when they say "You are beautiful" when I'm in pajamas and looking scruffy. I personally think I look fine when I'm not dressed up. But I have trouble believing anyone else could like me when I look like that. How could they? This lack of faith in other people apparently makes me seem very stuck up, which I don't want to be. I easily see beauty in everyone but myself. I know appearance is secondary to personality but doesn't everyone want to be good looking? Everyone puts on a facade in this world. Idk how to stop acting this way.