Yeah, pretty sure she had a Brazilian butt lift, not implants, although implants, I think, are a bit cheaper, so who knows. Plus, fat transfer usually includes stuffing the hip area (like Kim K and the likes), to make an hourglass shape, Lauren obviously hasn't had any fat put in her hips as they're quite 'bumpy' and natural looking (no hate, so do mine lol).
But she definitely had fat sucked out of her belly and the skin tightened, that's also why now, after gaining weight back, her belly is SO high up, she had all the fat cells sucked out of her lower stomach, so everything now accumulates farther up.