you will have to wait a number of months before it is fully healed and safe enough to re-tattoo. I have had similar problems with my tattoos, when I first got them they appeared to be filled in really good and nice and dark but once that thin layer of skin peels off you can see all the places where to artist didn't go deep enough with the needle. That all comes with experience on the artist's part. The guy who did the one on my back had over 30 years experience and there was very little ink loss that occured. But the guy who did the one on my wrist was young (i took a gamble with him) and the results were a tattoo that was quite blotchy. Luckily it's a small tattoo so it's not very noticeable.
LOL but my friend on the other hand, got his tattoos done by a coworker who tattoos on the side and his quality of work was terrible. There's huge lines and big white spaces on my friend's tattoo that the artist missed. Needless to say, that guy who did his tattoo isnt the greatest at what he does.