Re: tattoo fading. Speak to a tattooist about it, they can tell you what to expect for blurring etc.. The person who is drawing this is not the one who is going to tattoo it, right? Are they a tattoo artist? You will want to find an artist who is experienced with dot work. The less sun exposure to the piece, the better it will last.
Also, perhaps you can have an artist make a transfer stencil from the drawing. They scan the image/drawing into a special machine which then prints it out onto paper (in reverse) which can be placed against the skin & transfer the drawing onto you. Artists use it to trace the design with the tattoo machine when they aren't doing free-hand work. If someone is willing to do that for you, you could see IRL what it would look like on your back (though it would be blue/purple). Otherwise, photoshop?