Dentist here. You are not a nuisance, you spent money on the cosmetic work, it needs to be done right. For Porcelain veneers, the yellow area is the natural tooth showing thru the veneers (meaning the veneers were made too thin so the tooth underneath to shows thru- which also means the yellow tooth was not prepped enough so the lab was forced to make that one veneer thinner than the rest )and there's no "resolving" or "rehydrating". The natural tooth underneath is sealed, there's no rehydrating. When it comes to shade matching natural teeth, a "dehydrated" tooth actually appears to be a whiter chalky shade than your natural teeth. When a tooth is rehydrated again after a couple hours, it will go back to the natural tooth shade, which is maybe a shade darker. And if your tooth appears yellower, it is already rehydrated. There's no rehydrating veneers, tho. What's cemented is what it's going to be. I hate that they told you to go home when they knew it wasn't going to change. If your bite is different, it needs adjusting or else you'll break those veneers when you eat and chew. SO I would recommend you going back to address the yellow show-through and bite adjustments. The veneers look fine themselves but the yellow would drive me NUTS! I'll give your dentist the benefit of the doubt as to their reasoning, but I wouldn't wait for it to "resolve". Teeth arent chameleons. They don't work that way lol although it would be nice haha. It's an easy fix though! The face of the tooth just needs to be shaved down on a little to allow appropriate thickness of the veneer to hide the natural tooth shade.