Usually, including "upshirt" in your prompt results in a girl, looking at viewer through clothing's collar, and it's kinda hard to change it. I tried to fix it with lora, and got acceptable results for my use cases.
There are two versions:
Look — if you want to leave face in picture, but keep it over clothing
No look — if you want remove face completely, leaving only "under clothing" part
If you find it hard to remove face even with no look lora, you might want to use something like this in negative prompt: (face, head, neck, lips, mouth, eyes:1.2)
❗Also, DO NOT use the upshirt tag in your positive prompt.