Just to help with the image thing I think chesterpal said this (I’m sorry if I am incorrect! I just don’t want to take credit for finding this) go on this website:
Postimages — free image hosting / image upload
Resize image to 640 x 480 for message boards and copy the direct link
Then when writing on this forum there’s an add image tab thing the yellow picture of a mountain. Click that and remove the https//: already there and paste the direct link.
It will show as a link until you post it.
From what I know (which isn’t a whole lot and wait for second opinions from more experienced people) if the darker area is her fur, I think their fur can slightly change in colour over time. If it’s her skin it may be a sign of something else and I would say if you are worried take her to the vets.
Even if a hamster does everything normally doesn’t always mean they’re okay because they are prey animals they can hide pain. I’m not necessarily saying she IS in pain I’m just saying that it’s actually really hard to tell with hamsters. Normally though if something is upsetting their ears might go down and they may sleep more but that’s about it sometimes. Itching may also just be cleaning or stimulating the scent glands so unless it’s excessive I don’t think that’s bad.
I think a picture would help people to know what the dark spot looks like but if there is genuine concern something is wrong just take her to the vets to be sure.