Okay, he wasn't the type to be impressed. I sat next to him to show him my foot. — I just cut myself... — And yet there is no sign of an injury. How can that...? Before he had the time to finish, I took his hand and placed it against my belly. — Can you feel the difference? His fingers traveled over the surface of my skin and stopped where my belly button should have been.
I think the meaning is not very right.
I would propose something like the following:
Okay he wasn't the type to be easily impressed. I sat next to him to show him my foot.
— I cut myself a little while ago...
— And yet there is not a single cut mark. How can this...?
Before he had time to finish, I took his hand and placed it on my belly.
— You feel the difference?
His fingers traveled over my skin and stopped right where my navel should have been.
Your translation sounds more natural, less literal (eg : "very well" )than Kai Tachikawa1's, but as I'm not a native speaker of the English language I can't assume you're right and she's wrong.