Take your pruners and cut off all the vine ends and remove all the little pumpkins that you know won't have time to ripen, and see if that helps.
I just did that to my tomatoes, but it may be too late for them to change much.
One thing you might want to try with a green pumpkin...
If you ever read the Little House on the Prairie
books by Laura Ingalls Wilder, she told how an early blizzard was coming and her mother sent the girls out to collect all the vegetables, including the green pumpkins. She sliced them thin and put them into a pie with
apple pie seasoning, and their Pa asked where she got the apples for the pie.
If you try it, please let me know how it turns out. I read those books almost half a century ago.
Sue