Will you be refinishing the case? If so, You can re-glue and grain paint. I have done this with artist oil paints. It is extremley difficult but can be done. Glue, fill, stain, seal. Mix the background color and then streak the grain color in. I use a piece of glass as a mixing palet over the piece. Use laquer toners to even out the color, then finish. If you are not refinishing butterflies are the way to go but they will show forever.

Good luck
Ed