i wouldn’t be surprised if there was a fight. leos are very solitary and territorial, and unless you kept them in a VERY large enclosure, they probably fought.
for now, what you’ve done is fine. there isn’t much else you’ll be able to do until tomorrow. once she’s healed, i wouldn’t put her back in with the other female.
your dog needs a vet. he’ll need an antibiotic and probably prescription ear drops. while there, talk with your vet about preventative measures you can take to avoid this in the future.