I will be hidden from your face
The term "your face" represents God's presence. AT: "I will not be able to speak to you" (See: rc://en/ta/man/translate/figs-idiom)
a fugitive and a wanderer
See how you translated this in Genesis 4:12
vengeance will be taken on him sevenfold
This can be stated in active form. AT: "I will take vengeance on him seven times" or "I will punish that person seven times as severely as I am punishing you" (See: rc://en/ta/man/translate/figs-activepassive)
would not attack him
"would not kill Cain"