Kathleen V. S. answered 03/14/19
Spanish tutor with degree, bilingual work experience, lived in Spain
In Spanish the indirect object pronoun (le, les, me, nos, te, os) always has to be included regardless of whether or not the indirect object is specifically named. Also remember if the direct object (la cara) is not specifically named the le changes to se. So in your example sentence you would write “se la lava” (se refers to la niña, while la refers to la cara).