The best thing you can do first is flush the area with clean water for 5 minutes. You want the water pressure to be somewhat high and make sure it gets down into the bottom of the wound. Avoid soap and antiseptics, because these can actually cause more damage than good.
It's best to keep the wound covered after you flush it. You can put some antibacterial cream (like neosporin) on the wound and bandage with rolled gauze. I've included a link to a video below that shows how to bandage.
After you've placed the bandage, put a sock over the bandage and tape that on. This will help protect the bandage and keep Athena from pulling it off.
Change the bandage daily and flush the wound for one minute with water at each bandage change. You'll know the wound is almost healed when there appears to be no more depth to the wound.
If the wound starts to ooze pus, swells, turns very red or is not healing, then you'll need have a veterinarian take a look.
https://www.youtube.com/watch?v=BO5OCB5vGhgI hope that helps and Athena gets better soon.