Oh my goodness, I had a bad experience of this just recently. I was making a batch of cp shaving soap and put the pot on the larger element instead of the smaller (I hadn't soaped in quite a while and didn't think :roll: ) anyways right before my eyes the stuff looked...well....evil lol, it seperated so badly no amount of stick blending would do it justice.
In the end I left it over night, re heated in the morning and although it didn't come out the way I would have liked I was still able to save it.