Naw. I often think people are staring at me judging then realize they're looking at something else or more "through me" than "at me", yk? When I'm having a really hard time though it is VERY easy for me to slip into thinking they are actively shit talking me.
Like, ya I'll get glances. I think everybody does. And for context? I'm a transguy so I actually do look a little funky. Not just in my head, I swear. I will get glances that last longer than normal? From what I remember of "normal", lol. I'll even get a double take here and there. However, for how long I've been looking a odd? There has been a very VERY small handful of times where I've actively seen people pointing and talking about me as I've walked by. That has ONLY happened in rural areas, not counting the time it happened when I walked past an anti-vax protest. Okay.. and like once when I walked past these two girls in the street but to be fair I was stoned off my ass and doing a walk-dancing thing.
I'm telling you now. If people think you look ugly or weird as an adult? People are more uncomfortable than they are cruel. Children, immature people who. you. see. often. and the very mentally ill. Only they are openly cruel about apperances. A strangers discomfort may very easily spill into cruelty? But that is usually more in the form of not treating you as fully human, not open mockery. In north america, in my experience? It's just not done.
People will have fake frozen smiles. They will raise their eyebrows at their friends and try to subtly motion to you with mild interest or smirks. But people do not, simply do NOT, act the way you are describing that they act towards your friend. Other than the one spot I saw you say a kid called your friend ugly. Kids just suck sometimes.
It may be hard to accept, and it may be your friend is good at hiding her mental illness to not just herself but professionals as well(I know I was). But these types of thoughts are very concerning. I sure as hell know they're uncomfortable as all fuck and very harmful from experience. If these experiences are real I'd at the very least suggest she go to therapy to learn the healthiest way to cope with them.
Best of luck