[Jack_]

It's disgusting behaviour like this that I actually cannot stand.

Just remember one thing: their opinion is worthless. And they are worthless. Not you. Because whilst it may be easy for them to insult your appearance [which, by the way, is not at all bad], it still doesn't bypass the fact that they are all evidently irrelevant, worthless, narrow-minded little cretins that all have serious insecurities [hence why they pick on vulnerable people, to try and make themselves feel better]. You're a lovely, pretty person, who should not let a bunch of pathetic little kids belittle you into believing otherwise.

Oh, and I'm not sure how your sister would react but, hopefully, if she was a decent person, when you told her the situation she'd either tell him where to stick it [which by the sounds of it he deserves] or she'd tell him to stop it.