[souffle]

I'd try wiping it with a damp cotton ball. They sometimes exude more scent than normal especially if maturing, after cage cleans and also if they smell another hammy. Have any of those things happened recently? What age is she. It's very hard to tell from pics though so if you feel worried I'd see a vet. Just make sure they know about hamsters and are aware dwarf hamsters have a scent gland there! You would be surprised how many vets do not!