My neck lymph nodes are enlarged and very painful bilaterally due to herpes pharyngitis primary infection, how can I decrease their size? I have Advil (ibuprofen)

See your MD. The nodes are enlarged secondary to the infection and doing their job. There is no decreasing them until the infections resolves. I would think a course of Valtrex (valacyclovir) would help decrease your duration but see your physician asap.