Help. My inner cheek tissue and gums have become hardened due to what could possibly have been formalin, or some kind of fixative. From the research I've done it was probably something related with Formaldehyde or Paraformaldehyde, as there was a white precipitate on the bottom of the solution. How do I remove this from my inner mouth skin (mucous membranes)? It happened at a lab where I was supposed to get a sample of my saliva tested for infection, but the lady made a mistake and instead of just collecting a sample of my saliva around my salivary gland with a dry cotton swab, she submerged the swab in a liquid that had white precipitate at the bottom which she stirred and put into my mouth, probably because I said I felt my mouth was a bit dry. Since then my inner cheek tissue and gums are hard as a rock and when a bit comes off it tastes salty, and I can't find a way to make it back to normal. How can I remove or soften this, or make it peel off, given it is in a moist tissue.