Hi figgy11,
Wash that mold, dry the branch with a paper towel and let the tree in the open air - don't cover it again.
The tree needs air for that mold to vanish or it may come back.
After cleaning, just watch. You can't know if there was damage be it sever or light.
So let the tree do what she can .
Keep an eye on the tree if the mold comes back, clean it again and again. I'd use water only; you don't need any chemical. If the tree is still alive, she can take care of the mold.
Good luck !
By the way, that mold tells that the temp were too high under your protection. In the future, arrange for better temperature control.
To survive, fig trees just need a little tug and not a big push.