Ouch! That looks awful! I would get the vet out ASAP, because her hind legs look swollen- its possible some of the oozy bits are infected. You don't want that to turn into cellulitus, she probably needs to be on antibiotics and soon!
As for the skin issue, I would suggest washing all of the affected areas with either betadine or baking soda- something neutral to make sure you remove whatever is on her that is causing that reaction. You might try to clip some of the remaining nasty hair to keep it from getting in the sores so they can dry out and get some air- sometimes even just that will help kill bacteria.
The vet might have cream they suggest or compound, probably something with dex in it to combat the reaction.