Nothing to worry about. 8g is nothing. If she dropped under 600g, I would be worried.

I would try manipulating her environment to see if you can get her to eat, 700g is a bit little to go off feed. It is usually boys that size and girls of breeding size that go off feed. Try giving her different hides, or more hides. Change her tub to a smaller tub, increase or decrease temperatures. Fill the tub with crumpled newspaper or something.

A few months is nothing to worry about though. some go off feed from October-November through spring.