If you have Blue Kote, you can spray that on to hide the 'red' blood, which should help deter picking at it. Or you can flush it clean and apply an antiobiotic ointment (like Neosporin) without the pain killer ("caine") in it. The stuff with "caine" is toxic to birds, so don't use that. Keep her quiet and in a dimly lit area so she rests and just has enough light to eat/drink for a day or so. Keep an eye on her. If she continues to peck herself, there isn't much you can do about that and she will not heal. Chickens can recover from some pretty serious injuries, so all hope is not lost. Hang in there and see how she does in isolation and healing.