There's a fairly complex bit of theology and narrative tradition here.

First, look at Genesis 16.7-13, where an angel of YHVH appears to Sarai's slave-girl, Hagar. The angel is clearly identified as the LORD in 16.13, where she declares that she will call Him 'El-roi,' meaning "The God Who Sees," or "The God of Seeing." It is not just an angel, but YHVH Himself, making Himself visible in the form of an angel. This introduces the notion that God makes himself known, albeit not in His true form.

The narrative in Genesis 32.24-32, where Jacob sees God face to face, involves a lot of complex wordplay. For instance, Jacob's name in Hebrew is Ya'aqob, the name of the river Jabbok is Yabboq, and the Hebrew word for "wrestled" is Wayye'abeq, all words which are pronounced very similarly. Thus, the narrative is structured around Jacob's name, leading to a conclusion wherein God renames him Israel, or "The One Who Strives with God." "God Strives" is another acceptable translation. This replaces the name Jacob, which is a play on words from his birth narrative, meaning "He Supplants," something Jacob was known for doing (see Genesis 27). The Hebrew people, as descendants of Jacob, are portrayed as strong and worthy, because Jacob was the man who wrestled with God.

The story, in that case, is meant to represent Israel's never ending struggle with God, and not a literal turn of events. Jacob names the place where he wrestled with God Peniel, meaning "The Face of God," standing as a reminder that Jacob, who had previously been afraid to so much as face his brother Esau (v. 20) had now wrestled with a deity and survived. God helps Jacob to uncover and utilize his inner strength. This is portrayed best by Jacob's hip being put out of socket by God, something which does not stop him, alluding to the fact that Jacob's strength comes from within. All of this meshes with 16.13, pointing to the fact that Jacob did not wrestle with God in His true form, but with a representation of the deity, as the story is a representation of man's every day struggles with God, and how God helps us to find our inner strengths. There's no doubt it was meant to be taken literally as well (take, for instance, the etiological conclusion that Jacob's battle is the reason for the prohibition against eating the thigh muscle) but the truth of the story is entirely secondary to the theological conclusion, which must involve only a representation of a deity.

We can use Exodus 33.11 as a further indication that "face to face" does not literally mean seeing God, but rather talking with Him personally, rather than within dreams or visions. Moses is said to talk with God face to face despite the fact that in 33.20 God tells Moses that he cannot see the actual face of God. Thus, YHVH shows Moses his backside.

In John 1.18, the Johannine writer claims that "No one has ever seen God," not mentioning His face. This claim is repeated in 1 John 4.12. The Johannine philosophy is that God resides within, and the manifestations of God are not God Himself, but merely parts of God. God is unknowable in form, but can be seen through Godly actions. Physical manifestations can be seen (I.E. Jesus Christ). These manifestations can help to make God known, but they are not, in actuality, God in his true state.

Hope that helps.