They don't walk up and bite you.
It doesn't take chunks out if you do get bitten, just teeth-width slices. Don't worry about if it will hurt. I have owned 35+ hamsters, many of them not tame when I bought them, and have only been bitten once, so it is very rare if you treat them right.
If she mistakes your finger for food, it will not hurt. It would just feel like she was trying to pick something up... this does happen sometimes, but don't be alarmed... I just move my finger to let them know it is a finger. These are the same teeth that mother hamsters use to carry babies back to the nest gently... and when they think your finger might be food they take it gently too...