my iddy biddy tattoo

I had a tattoo done in january. It's a tiny chinese symbol meaning happiness.It's very small and needs filling in, as there's lots of white little gaps where the scabs got rubbed off in my sleep, as it's on the bottom of my spine. I know everyone's got a chinese symbol so I'd really like to add to it in some way to make it a bit more interesting: maybe something creeping up a bit from the original in the same sort of style so that it makes sense, but I don't know what. Can you suggest something? thanx, lucy, england.