Well that's kinda a loaded question...  A lot.  A lot is wrong with Steve's face.  But in addition to the normal things wrong with his face, he had a few mishaps while on vacation.

First off, he broke his 3 front teeth off.  Don't worry though, they were already broken off in the first place.  About 10ish years ago, Steve face planted and knocked his 3 front teeth out and while he was on vacation, his implants decided to fail on him.  So he had to go back to the dentist and get it fixed!

But it didn't get totally fixed...  yet...  Right now he has some plastic temporary teeth until he can go back to the dentist in a few weeks and get completely fixed up with his brand new crowns.

Now the story goes a little bit further...  Steve isn't allowed to use his current fake teeth for chewing, so he has to eat only using his teeth on the side of his mouth.  Well, that caused Steve to burn the heck out of his lip when eating a slice of pizza.  So now Steve has 3 plastic front teeth and a massive burn on his lip.  So that's what is wrong with Steve's face.  Check out the pictures: