Hello, about one and a half weeks ago my 2 year old son dropped a heavy toy on his big toe. he had a small scratch at the cutical and a little bit of brusing. Instead of everything healing and going away. He now has discoloration under his nail. It is black right next to the cutical under the nail. What is this and why hasn't it gone away? Could this be fungus? I don't want to have to take him to the doctor if this is nothing to be concerned about.