If the recent photos of her are completely genuine and haven't been altered in any way, then it does look as if work has been done - her eyes appear slightly longer in the more recent pictures and her cheeks also have that slightly 'stretched' look that you get in cosmetic surgery. But as she is still young, you don't see the major differences that you would see with an older person, so it is always possible that she hasn't had actual surgery. Botox, probably yes.
There are stories that she has admitted to surgery, but nothing official (it's been said that she had more work done after her last relationship ended). Her lifestyle is very much about self-presentation, and it's hard to see why, if she did have work done, she would have a problem with admitting it. Either way, at the moment you can say it's very probable but not sure.