What Causes Muffled Hearing After Teflon Grommets Fitting?

Hi, may I answer your health queries right now ? Please type your query here... My husband (age 64) had teflon grommets fitted 3 days ago because of eustachian tube dysfunction. He has had no pain, bleeding or discharge but is complaining of muffled hearing and a sense of ear fullness. Is this normal and how soon will it resolve? Kind regards, Polly