It's tough to tell if it's from and injury or somthing else. I would do a large water change, and then treat with 1 tabelspood of aquarium salt per 5 gals of water. This should excelerate the healing process. If the sore is really bad or appears open you could also, in addition to the salt put some Iodine directly on the sore.
I just saw this post. In the future you could just "Bump" the post after a day if you've recived no response. If you alienate the members people will be less likly to respond to your threads, however I understand it can be frustrating.