This is a terrible way to find out that box turtles should generally be kept apart from each other in captivity; especially youngsters.
In the wild box turtles almost never interact with each other; rather, males wander through their territory looking for food and mates while most females remain static within a 300 meter polygonal shaped territory. When males interact with other males, they fight. When they encounter females, they reproduce. It is HIGHLY unusual for multiple box turtles to be found in the same territory unless forced together by habitat destruction/fragmentation and causes undue stress due to increased competition for limited resources (cover, concealment, food, water).
This is exactly opposite the condition you find with spotted, wood and pond sliders.
It is best to raise young boxies separate in order to control food intake and monitor their health; not to mention the potential for injuries resulting from bites. The type of injury you described could very well have been caused by another boxie.
Ensure also that you keep boxies from different species and geographic areas separate from each other; the potential for spreading zoonoses and various bacteria and parasites between turtles is too great a risk.
I hope your turtle heals quickly; we have dealt with several one-eyed and blind boxies and they learn to do quite well with limited or non-existant eye sight. Ensure you are also providing the turtle with a good oral antibiotic such as Baytril as well as a veterinary-certified ophthalmic ointment (such as (Ciprofloxacin)
Dennis Desmond
Director of Operations
Northern Virginia Reptile Rescue

Northern Virginia Reptile Rescue