The fur around my gerbil's left eye is all red, like it was bloody or something?

My gerbil kind of flew across his cage last night, and now his left eye looks very hurt. It is not opened all the way, and the fur around the eye is all red. I don't think he got in a fight with his sister, because there is no bight marks, or scratches on him. It looks like he bleed out of his eye or something. Does anyone know what is happening to him? Or how I can help him? I can't bring him to the vet, because I am 14. Thanks for all that help.