I am not happy with an implant. The area where the implant was placed is dark, since it is my front tooth it is noticeable.

I had a dental implant done where I am not happy with it. The area where the implant was placed is dark, almost gray, and it is my front tooth (#9) so it is very noticable. I am not happy with it, and of course this was a very long and expensive procedure. The doctor that placed the implant assures me that this isn't the implant showing through, but, what else could it be? What are my options?