Due to her baby face she clearly from a makeup point of view, contoured to have better cheekbones appearance-wise. But once the Boys fame hit and she was more in the spotlight and had more money in her pocket, she just sped things along and got buccal fat removal. And well, plastic surgery is like tattoos, once you get one you don't stop.
And now she has breast augmentations, the fat removal, lip injections, etc. The ironic thing is that these surgeries age you more causing people to get stuck in a vicious cycle of repeated procedures or else look ten years (or what have you) older the moment they stop.
Personally, I can see why she got the work done. Feeling self-conscious about her small breasts and not wanting to look like a teenager her whole adult life with that baby face. So essentially, she wanted to look like a woman and not a girl. And well, like many she went a bit too far in part because she is in the spotlight due to being a celebrity. Taking a break from social media should (hopefully) do wonders for her self-esteem.