My mouse has a ear problem?

Question
Ok about four days ago I was going to go to my friends so I said good bye to my two female mice and put a cardboard box in there because I wansnt taking them out that night the box had tissue paper, toilet paper, paper towels, and some cardboard. The next night we took them out and I noticed her ear was very pink and raw and she had lots of scratches on the inside of her ear and one on the outside I noticed no other hair loss nad her other ear was fine two nights ago I didn't check on her but I seen her the earlier and see seemed fine yesterday night my mom and I took the girls out her ear was already looking better I had not done anything to it but that night i cleaned the inside and outside of her ear really good with room temp water and dryed it very good I noticed some of the normal pinkness coming back into her ear the scratchs were healing or gone and again no other signs of hair loss I was wondering what it could be from I would like the vet to be my last resort because of the time it takes to get there and get back and her being so high stressed I don'ts want it to be to much for her can you recommened any more home treatments?
And maybe even how to transport her safely to my vet its about 30 minuet depending on traffic she will be in a small box it will be dark and quiet and her sister will be with her.

Answer
There are many causes for ear wounds, and you can go to the below site for a ton of information! This pretty much sums everything up, except that it does not mention ringworm. If lesions come back I would suggest taking him to the vet...getting him seem would be a good idea anyway. If she has mites or lice she would need to be treated as well. First, check out the below site...

http://www.thefunmouse.com/info/hair-loss.cfm

There is also a chance she could have cut herself on the cardboard. You can cut yourself on cardboard. It's like a paper cut, but a lot worse. Then there is the chance that the other mouse could be barbering her, and causing irritation. If you have any further questions feel free to ask. :)