I would be honest and tell her if its actually ugly… for example, she got red highlights in her hair and her hubby bleached his hair blonde 
… I didn’t see him while his hair was bleached but when I saw her with the red highlights, I told her it didn’t suit her … and she just wasn’t ready to believe… she was like “*pehla banda hai jis ko pasand nahin aya, so-and-so said its lovely, so-and-so said its so glamorous!” *
I can’t have an attitude like MIA’s, i wish I did, but I really get upset when I hear this kinda stuff so thats why I just go to my room now whenever they come.