Give it time, the pumpkins will rot a bit more and get soft and the worms will move in.

for the worms, they appreciate the secrets of a good cheesemaker and vintner: time brings out well-aged flavors and full-body taste

I know this is an older post, but I am interested in pumpkins and worms because mine love pumpkin so much and I am going to grow some just for their consumption this year. I wonder if treated seed (treated with Thiram) which the professional pumpkin growers might use would have an adverse effect on their taste? I also have a tendency to hold my pumpkins until mid December, but since your post was Nov 16, I'm not sure a month is all that important. I read somewhere that they need to freeze before they taste good, but I'm not sure it's true, just throwing it out. Last year I grew cantaloupes and watermelon for them. Well, we shared the harvest you might say, but then October, November, Dec., etc., came along and I didn't have enough for them to eat. Luckily a friend had some organic pumpkins for me which I had on the front porch and later cut up and froze. The skin of pumpkins has a lot of wax in it, I think. Now I am excited to grow my own!