FYI in general you shouldn't go from 220 grit to 600 grit (green pad). 600 will smooth it out a little but not much. There's too big a gap in the grit level. These low number are very rough in terms of bowling balls. You should probably do 220, 320, 400 and then 600 grit next time. If you weren't doing on a spinner, you probably shouldn't do that anyway.
I think the Blue Hammer was in the 600 - 800 grit US range. I'd ask the pro shop to take it to 600 grit, but tell him what you did so he knows where to start.
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"None are so blind as those who will not see."