Actually, Leguna didn't plan on staying in the camp for that long a time. But since Eirinn had just recovered from shock, he decided to let her rest for a few days before leaving.
He didn't think she would turn back to normal so quickly after he returned. In only one day, her face was healthily flush again.
It shouldn't be surprising, however, since Eirinn was a 12th-stratum priestess. Even though her constitution wouldn't be able to compare to that of warriors, it was still far superior to average folks'. She was also divinely favored and would always be protected by Pyro's sacred light. So, her injuries weren't significant problems to begin with. She had easily recovered with a day or two's rest.
The problem lied with her mental scars. The sudden siege, close brush with a deranged Alpacino...