Hey sorry I didn’t get back to you regarding your gals toe with the sore on it. My mare was really sick

Anyways here is my thought, it looks like she has caught it on something and cut it, she would then pick at it making it worse.
If you can soak it in warm water to clean it, then use some antibiotic ointment that you can get from any pharmacy, put a small dab on it and if you can put a small bandage on it - if you can’t it a bandage on it then rather than ointment, spray with blue coat.
Ok let us know how it goes.