You must have mixed the goop in incorrect proportions - I've used goop on several boats and it always cured within a day or 2, even in cold garage.
I think you have 2 options. I know that epoxy mixed in (slightly) wrong proportions will cure eventually, after a very long time.
So, your first option is to keep on waiting, and perhaps apply heat along the way (space heater, heat gun?)
If the goop has not cured in 2 weeks, your additional wait time may be measured in weeks, if not more.
What is your workspace temperature, BTW.
The second option is to bite the bullet and start over with new skin (that's what I'd do)
I don't think there is any chemical catalyst that will magically cure the uncured goop.