Even if it's a small area you should wait ~3 weeks to let it heal. You risk bad healing due to tattooing on crust (think of as the top layer of old snow, and you stick something through it. It cracks on bigger area than the thing you stick through it). When the crust has fallen of it's still sensitive, you shouldn't tattoo it during "snake skin" stage either
I only have one experience of finger tattooing and found it very difficult : strange skin type, hard to stretch, hard to position myself.
And one experience of tattoing back, the day after, and i did cut my wife's skin over a few millimeters, using a 5RL( but i guess needle size didn't matter).
So i think you should wait and read about the subject during that 3 weeks period.