Maggots will be present in the wound, under remaining skin, in the vent if the wound is nearby, and eggs and little maggots will be hatching out every hour, so it's a real emergency!
Wear gloves, rinse, pull them out individually, and look all over her body, because those flies will have layed eggs elsewhere too.
One day to hatch, one day to grow by destroying tissue right to bone, and produce toxins that will cause death.
Use an insecticide like permethrin, as part of the rinse.
Then treat with Neosporin, maluka honey, or Silvadene, to cover all the damaged tissue, house her on hospital pads or towels, and keep her eating and drinking.
It's survivable IF it's treated immediately, and not secondary to an untreatable malady.
All the best,
Mary