(This is modified from something I wrote to someone who says negative things about their looks -- but it applies even if you only do the 'positive' side of calling some people attractive.)
When you say you are ugly, I hear that you believe in a such thing as ugliness, and I know that I am not safe to be beautiful in your eyes. I know that if you call me beautiful, you might be using that as a way to harm your own self with comparison. How can I appreciate admiration if I know it might not be about me at all, but just the underside of you condemning yourself? I can't bear to be looked at through a lens of relative ugliness. If you hate your belly for not being flat, my poky belly is not safe in your gaze. If you take issue with the shape of your jawline, my 'double chin' is not safe in your gaze. You might not see it as ugly, but since you believe in ugly I can never be sure.
It is not fucking true that you are 'ugly'! If you are not willing to accept that it is a lie shoved into your head by cruel evil people, you can't get rid of the idea. It's a lie it's a lie it's a lie it's a LIE. Reject it. Even if you can't help that it repeats in your head, please decide it is a lie repeating instead of truth repeating. Please. You holding this lie close to your chest keeps people from being able to communicate with you about how they feel about you. It's like a giant shield that blocks out affection and admiration. You probably can't just throw it out. It probably feels like a kind of protection. But you can turn it sideways (decide it's a lie) so that people can get past it. You can accept that the people who love you are more honest than the people who want to abuse and control you. You can decide that all ratings are LIES. EVIL, CRUEL lies.
There is NO SUCH THING as ugly. There is no such thing as a body 'flaw.' YOU ARE PERFECT. Variety is beauty. You could not be more beautiful if you were different. People who think that there is a such thing as more attractive and less attractive have fucked up wrong perceptions that they need to change. No one gets to fucking rank people's attractiveness! NO ONE EVER. Not even you.
Also, that celebrity or model or whoever is NOT more attractive than you. This is as wrong to say as it is to say that they're uglier than you. It's creepy to compare like that. Nobody is more beautiful than you. There is no such thing as objective beauty. "You are beautiful" always and ONLY means "looking at you is enjoyable for me." Rotten people might get more enjoyment out of looking at people who resemble the societal ideal of the moment, but doesn't make it objective. Rotten people's opinions are irrelevant to actual life and love.
Do you compare you and me? do I gain attractiveness if I lose weight? If my belly is smaller? if my neck is thinner? if I wear makeup? If you judge everyone as more attractive than you or not, I have a really hard time believing that you don't judge me. I have a really hard time believing that you can do this comparison thing so often and yet have it not apply to me. Even if you did though, I would still be really bothered by the comparison for others. And because you believe in 'ugly' every time you use an attraction word (pretty beautiful cute gorgeous) as if it is objective, it feels AWFUL to me. I feel hurt for myself, for you, and for whoever you are judging as 'more attractive.' If attractiveness can be ranked, then I can only be beautiful at the expense of others. That is never something I want.
As with telling me you love me, only tell me I’m beautiful if you mean it. And challenge yourself to mean it. Recognize the way it stretches you to call a fat person beautiful, not as an exception, but as a shifting, growing rule. Feel all the things you are rejecting by saying such a simple, common word. - "What happens when you call your fat friend beautiful" by thefatshadow on Medium