Wow, that’s a tough one.
I would probably sandlbast the piece, but you’d have to take it up to a higher temperature to get the shine back, and if it were draped over that mold, it will pick up the texture of the mold. What you’re seeing is most likely devitrification or crystallization of the glass. The only way I know to get rid of it is by sandblasting and refiring, but the fact that the piece was draped OVER a starfire mold is what’s causing the difficulty in fixing it.
One thought would be to sandblast and firepolish with the bowl turned up, without the mold…it should flatten in the kiln and create a flat piece again. It should also become shiny again. Once cool, you could slump again over the starfire mold at the same temperature you used initially.
I wish I had a better suggestion!