Gots a busy day so this is short but...
Hydrogen preoxide is fine. Just keep a watchful eye on it. If it is semi-bad or worse you may want to keep her isolated in a small cage with paper towel for bedding for a couple days. Or at least use soft bedding in her cage.
If you want you can apply a small bit of neosporin to the area but make sure she does not really lick that area, maybe give her a yummy treat to keep her occupied for a few minutes while the neosporin sets in.

If she gets any swelling take her to the vet it may be an abcess.