I see, my mistake
In that case I'd just remove the lightish pixels from around his ears; they look more like a mistake than part of the official art.
Also I notice that the Pikachu on the official art has sort of a more menacing look than yours, I think because he tilts his head more downward?
If you have too much contrast to the background, then it starts competing with the main focus and possibly starts to hurt your eyes, so I'd just leave it. But it's up to you.