Mrs Clayton is a 41 year old female who presents to her GP surgery as she is concerned that her face has become asymmetrical. She also reports a two day history of a dull earache and feeling of fullness on the same side. On waking this morning, she noticed her eyebrow drooping and difficulty in closing her right eye. She has been very stressed at work so initially felt her symptoms might be related to this, she spent the last few hours in bed but symptoms persisted. Mrs Clayton has Irritable Bowel Syndrome but is otherwise fit and well. She does not smoke or drink alcohol.
On examination, there is drooping of the eyelid and corner of the mouth on the right side of her face. She is unable to completely close her eye, smile or wrinkle her forehead. Ear examination is unremarkable, and the remainder of her cranial nerves are intact.
Based on the most likely diagnosis, what is the most appropriate treatment?