Wow, the new ink practically covered the old piece completely: So the bottom part of the "before" is in the mouth, and the upper hook part of the "before" is just under the eye, right?
I simply love your style, how the lines and everything compliment each other. An tattooing colleague once shared a great tip with me that he learned from someone else: never let dark touch dark; and you showed how great that theory works here.
It's always hard to give constructive critique on a finished tattoo; since it's can't be erased, and one shouldn't risk the "canvas" losing their confidence in the artwork they'll be wearing for years.
I suppose one could share what could simply be added to the tattoo: So, if I was the wearer, or the tattooist, I would of wanted the line at the top of the head, that separated the ear with the white fluff, to be extended a bit, so that ear might have a more balanced presence.
And maybe to help add even more balance, I would probably make the white tuff either part of the blue fur or part of the yellow insides of the ear, since it makes the non-tuff ear feel a bit naked to me. (Even though it would of been perfect as is if there was a white tuff in the other ear as well).
I mean, it wasn't stunning or anything, but it didn't look that terrible. if it were me, I would have taken the original and expanded it into a sleeve, or incorporated it into another design before I decided on ultimately covering it up.