How can I do this?

[mint condor]

I would use either the generative fill (edit>generative fill) after having circled the area and leave the prompt box empty (no prompt)
The more precise you are in your selection, the better the result.

alternatively, you can use the remove tool, which also use AI to function

again, precision is key!

[sly otter]

Yeah, remove tool works well. - Also check out neural filters, to change the smile 🙂