Agree. It needs looking at by a vet. I can't tell what it is but may be a prolapse. It needs to be an exotic vet really as they know more about hamsters.
In terms of "binding" foods, yes hamsters can have the odd bit of banana or scrambled egg
Just a tiny amount - maybe a little bit on the edge of a teaspoon for the scrambled egg. Just fork whisk an egg in a mug and add a bit of water, then microwave it - better done with water than milk as they don't tolerate dairy products well. I can't remember how long I microwave it - but maybe check every 10 to 20 seconds as its such a small amount. Let it cool before giving it as well. Banana - just cut a slice of banana and give about a quarter of the slice.
She still needs a vet to look at the back end though.