Green spots on pumpkin, what to do or how to prevent?

Nothing, it is starting to turn orange. Needs more time. Depending on the variety of pumpkin, I have had mine do this too.

Your 'baby' is an adolescent!

This actually looks to me like a mosaic virus, and there's nothing you can do. The squash family is notorious for plant diseases of this type. Many of them cause discoloration like this. It could continue to develop and do fine, and change to its mature color, but there could still be some spotting. Or it could fail. If you see that its future is not good, you can always pick it early and eat it like squash. It will be safe to eat. I am a vegetable farmer.

If you can wait another week, just pick it and spray it orange-I would do the cut-out face then when you cut and then spray