How long is "some time"? Are we talking a month or 6 months?
There are a few things to look at: What kind of heat source do you have? What is the bedding? And what kind of food is she eating--was it a change from the breeder's food?
Sometimes if the air is too dry in a home, it causes dry skin on hedgies as well as people. Various heating sources and weather conditions can cause it. If the air seems dry in your home, you might try a humidifier in the hedgie room.
Wood bedding can cause dry skin, so if you don't have her on liners you should switch to those.
Sometimes dry skin can be caused by allergies to foods. If you've put her on a new food in the past few months that could be it. Crusty patches on the face are a sign, as well. And sometimes strong-smelling poop, often grainy, is also a sign.
How often are you bathing her? Oatmeal can help, but bathing too often can dry out skin too. When you do bathe her, try rinsing with flax seed oil at the end (can be bought in capsules in the pharmacy section).
If you haven't made any recent changes and none of those things help, or she starts losing quills/having other symptoms, Immortalia's suggestion would be the next step. First I would start looking at environmental causes, however; if none of those seem to be the culprit, the vet is the next step.
yes the vet has checked her, no mites, no bacteria 100% healthy. he just thinks maybe stress, but she doesnt seems stress at all with me, could be the weather change down here.. anybody know anyg good oils to use when bathing?