Part of my facial expressions series. All of these LoRAs are designed to mesh well with each other and have low impact on your image framing. Newest version should have much less "Same face" subject transfer, and more variety.
Lower lip bite off to one side. I recommend not adding expression in most cases, but it may help in some. Bumping up 1.4 can help if the expression isn't coming through.
Starter Prompts:
<subject>, lip bite
<subject>, lip bite , teeth
<subject>, biting her lip
Somewhat counter-intuitively, teeth is sometimes a really helpful negative word and sometimes useful in the prompt, depend on whether you're getting too much or too little. smile is also sometimes really helpful as a negative if you have a particularly tooth-y / grinning-by-default subject.