He hit me in the face

My boyfriend has bad night terrors because of his past. He tends to talk in his sleep. My mom told me you aren't supposed to wake someone up who is having a night terror. He was having a really bad one last night and was hyperventilating so I tried to wake him up and got punched in the eye. He was really apologetic and felt awful. I don't think he hit me super hard. I do bruise easy though so I now have a black eye. My mom asked what happened and I said "Allen did this to me, but it's not what you think". She told me I told you so about not waking someone who's having a nighy terror. Was I really supposed to just let him continue hyperventilating?