I'm sorry but how is being "at wits end" an excuse to use punitive dog training? While it may be a stress reliever for the human to be take it out on the dog, it doesn't actually help the dog understand anything. In fact if the dog is asking for ATTENTION you are actually rewarding the biting by giving them what they want (attention - even if it's negative). In fact, a time out is actually "punishment" because you are taking away what the dog wants (you!). This is why I was on the fence with the lip curl (though I have used it and would potentially try it here as well).
Behaviors like this can rarely be fixed ALONE without also looking at the dog's overall routine. Often it's a symptom of a greater "need".