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Angelthehamster that is quite unusual as it is something they do normally grow out of, do you feed her treats from your hand?
I don't think you can do much else other than really try hard not to make any sudden movements & only gently discourage her, don't put her back in the cage straight away. I would try just gently stroking her & nudging her mouth away from your hand.

Culprit you've only had your ham a few days so nibbling would be perfectly normal, if you pull your hand away you may just scare him, he should soon learn what is & isn't food so for now if he just nibbles rather than bites ignore it or do as I suggested above.