Good Day,
My daughter has OLP and has been given IVIG treatments over a course of two years. She has definitely seen improvement and remission. We will have to see if that is long term at the end of the treatment.
On another note, one of my dental hygienists recommended clove oil to help relieve pain and prevent infection after a dental procedure. It seemed to work for my situation. You mentioned alternate options so I thought it might be worth mentioning.
Hoping you find some relief.