Sometimes you have to do things that may be unpleasant in order to get done what needs to be done.
It needs to be cleaned really well. Irrigated. Then the feathers need to be trimmed away from the edges so we can see what we're working with. Once the wound is clean, then apply a very thick layer of the plain triple antibiotic ointment. If you think you have enough, apply more. I squeeze it directly onto the wound and then gently pat it around. It likes to stick to your fingers so you have to sort of drag it around and pat gently to get it where it needs to be. Do NOT let the wound dry out. Reapply the ointment as much as necessary.
With how deep her wound is, and where it is located, there is a chance that this could be worse than we realize. Keep that in mind.