Possible Clues:

• Tolkien's Treebeard, e.g.
• Talking Tolkien tree
• Doc for head colds
• Suffix with insist
• Fangorn Forest creature
• Sinus specialist: Abbr
• Student of Elves, in Tolkien
• Dr. who treats sinus issues
• Rhinoplasty doc
• Tonsillitis M.D