And Dr Richard Marques says he thinks Stephanie, 28 - who has never talked about having plastic surgery - may have had quite a few procedures.
He tells Closer: "Stephanie's face has definitely changed shape - her nose is a lot slimmer, signifying she may have had a nose job. Her cheeks were always full but they are a little more plumped up, suggesting cheek filler and it looks like there is filler in the lips too as they are definitely bigger. Stephanie looks like she has also used semi-permanent makeup and had her eyebrows tattooed. In both shots, her teeth have been whitened."
Stephanie, who is also rumoured to have had a breast augmentation and a chin implant, could be following in her sister-in-law Heidi Montag's plastic surgery footsteps.
Heidi famously underwent ten plastic surgery procedures in just one day in 2010 and broke the news to her mother - who barely recognized her daughter - on US reality show The Hills.
However Heidi admitted afterwards that she wished she hadn't gone to such extremes to change her looks.
She said: "I definitely regret the surgeries that I have had over the years, I think I was so young and in such an unstable situation in my life with so much going on and so much pressure."