After reading your previous thread, you are really going to have to change a few things around with your husbandry. Turtles are survivors and in general are pretty tough animals BUT.....they still can become sick with improper care and it can take months to years before they show any signs of it and sometimes that can be too late.
For starters box turtles really don't thrive indoors.....at all. But, since you can not keep your turtle outside (I believe I recall you saying that you lived in an apartment) you are going to have to duplicate the outdoors for your turtle. Letting it run around loose in your house is not a good idea and is unnatural. You are going to have to make an enclosure for it. This can be anything from a stock tank to a larger rubbermaid tub. Your turtle needs proper humidity levels that the normal house hold does not supply. You will need a thick layer of soil for your turtle to bury into. This is what it's trying to accomplish when it hides in the dark corners of your house. I would recommend buying bags or bricks of Eco Earth. Second, you must have UVB lighting for your turtle as well as a basking light if you don't already. UVB is very important for turtles because they need it for making vitamin D internally. If not supplied with it, they start taking it from their bones and they intern get MBD. This is what happens when you keep them indoors without exposure to unfiltered sunlight.
I would start feeding your turtle things that have vitamin A in it. It helps with the healing process in reptiles. Feed foods like grated carrots, yellow squash and zucchini. Also try feeding your turtle thawed shrimp. Also make sure you are dusting the food with reptile vitamins. I would pick up a bottle of Zoomed Turtle Eye Drops. They contain vitamin A and will help with healing. Just apply them to the turtle twice a day.
If you are willing the change a few things around I'm sure it will help to give your turtle a fighting chance.