Hi,
Just wanted to add my 2c and say I would take her to the vet as well.
It definately looks like either scale rot or an infected burn in the video but you can't diagnose an animal over the net with any certainty.
I would double check all your heating elements for hot spots or failures and , as you have already done, put her an a nice sterile tank on newspaper or paper towels you can examine and change often. It's a very large area to try and treat yourself and I think the vet would be the only realistic option till it is a little better controled.
Hope she turns out ok.
dr del