"Rafael, lávate la cara, por favor."
Translation:Rafael, wash your face, please.
Sometimes they have only got around to adding one translation; sometimes they want the "tú" conjugation because the person is being addressed by name and not by title. However, the formal imperative is lávese.
As a (near) middle-aged American, I am not sure how well using the first name as an indicator gets across the distinction between tú and usted. I cannot think of anyone I would refer to in any other way. It's been over a decade since I used Mr. unironically. Yet, in Spanish I would use usted with many people I call by their first names in English.
It is difficult for me also. Friends and family are easy but what about the housekeeper or the coffee shop i go to weekly. One suggestion is to wait for them to address you as tu first. Would like to hear others viewpoint.