Saying “Ouch!” is not working. Help!

Hey y’all,

First time pup owner. I have a 3 month fox red Labrador retriever, her name is Artemis and I love her dearly! She is currently a nightmare when out of her crate when it comes to teething though and I’m seeking advice! I’ve been told to say “ouch!” And/or yelp like a puppy when she bites, and not to move, and when she does move to walk away and ignore her for about a minute. This does not work for me because when I do this, she always just goes and finds something else to chew on. Is the solution to always have her in the ex-pen during this phase, except for crate time and outside time? It happens when we’re outside as well, which makes it much harder because I can’t just walk away, or she can just find a stick or a leaf to chew on. Please be kind to me, I’m new to all of this! Thank you!