When my chick had a wound, she would scratch at it too, and by the end of the day, the wound was covered in dirt. I cleaned it at night and applied coconut oil. In a way being covered in dirt protected the wound. Your chick is different.
Instead of dirt, an antibiotic may be recommemded at...
Maybe post a picture of the wound? If the scab isn't ready, keep it clean twice a day. Her scratching at it could mean it is healed, or still healing.
The scab will come off when it's ready, or you can try to pry it off with a toothpick gently. When healed, the skin underneath will be smooth...
Coconut oil is a natural antibacterial and will prevent infection. Clean the wound of all dirt with a toothbrush and water if necessary, then apply the oil once or twice a day with a small dab from a toothpick or something. It absorbs into the scab and you'll see a nice improvement almost...