It’s difficult to understand the question. “I want to do this right and not offend anyone.”, that’s nice, and especially nice when @cringeworthypoet tells us her friend is insecure about her body and that @MargaretInCanada was bullied.
I have a friend with vitiligo, but I never realised that because all I see is her smile, as she’s one of the friendliest people I know. When she leaves, the day is always brighter. I love her for what she does: always a kind word, never complaining, always cheering everybody up, just by being there. For me, this is one perfect woman. Perfect is not how we look (that’s just an image, created by people who sell products, thanks to our insecurity). Perfect is how we act.
When someone bullies you or makes you insecure, this says more about him than about you: intolerant, arrogant, feeling himself better than anyone who’s ‘different’. I prefer not to pay attention to such unpleasant behaviour.
So, to answer what I hope is the question: you can check Wikipedia etc for all the medical details, and you should work on that to get it right, but if you want to write a good story, add some ingredients that make your readers feel perfect because of what they do and not because of how they look. I wonder why we tolerate intolerant people (yeah, because we’re tolerant ourselves) and I wonder why we listen to anyone who says bad things about others while on the other hand we hardly say to other people how nice and friendly and beautiful they are.
I think I’m more aware of that now and I’ll do my best to change my own words from now on, be more intolerant to bullies and pay friendly people a compliment for their kindness.
That’s the task of a writer, making readers aware and giving them ideas that help us make our lives and the lives of others a little better. I think you did a good job here and don’t worry too much: you have what it takes to write a great story and your readers will love you, for what you do, not for how you look.