A lot of medications cause weight gain, especially anti-depressants. It's possible that they also altered her body chemistry and that has now changed how fragrance smells on her. She could probably still be using the same perfume, but it is now mingling with a different chemistry, which is the major factor in how a fragrance smells on someone, anyway.
Hot chick in the city.
Oh, oh, can't you see? Love is the drug for me.