You're right, it just means وَجْهُ, the verse states:
فَاغْسِلُوا وُجُوهَكُمْ وَأَيْدِيَكُمْ إِلَى الْمَرَافِقِ
Which is, "then wash your face (وَجْهُ), and your hands, up to your elbows".
So in 4:43 when it states to wash, it is the wash God has described here in 5:6 then isn't it?