Got my implant crown today & it now looks grey, how much does it normally cost to go back in & get a different shade? (Photo)

Originally I was quite worried about my crown not being the right size compared to my very small teeth so when I looked at my crown while it was being placed with temporary cement I was focusing more on that. I have now noticed a grey-white tint to the crown compared to my teeth which a yellow-white tint. How much is it to go back in and get a different shade to make it match my shade better? The color I originally choose matched my teeth very well so I'm not sure why it's grayish now.