Weigh her tonight on a gram kitchen scale and again in three days, and count the droppings while you are there. A hamster that is eating less shows it in the weight and in fewer, smaller droppings before it shows anything else.
Also look at both cheeks from the front. One side staying swollen when the other has emptied, or a lopsided face, is a pouch problem rather than a tooth one, and sharp or sticky food is usually how that starts.