If it happens again, another little trick that works most of the time, is to put some acetone into a paint gun and spray a light coat over the fiberglass. Not wet, but not quite a dust coat, kind of an in between coat. I don't know why, but this allows it to flash off within a few hours. I don't remember where I heard this, but I've used it on automotive parts and it's worked great with both polyester and epoxy resins.