Hi, I had dental treatment almost two weeks ago and thought that the carbon-treated paper used to check for the fit of a replace filling was responsible for the black marking at the back of my tongue. But it s still there! Now I m wondering if it s linked to the stringy slime I ve been experiencing in my mouth over the last few months, which I never used to have. Some days I find that there is skin-like stringy dicharge in my mouth. Never had this before and haven t changed my usual toothpaste or mouthwash recently.