You need to go see your primary care doctor
or your dermatologist
about this issue. Any persistent medical issue, include a skin rash, that is unexplained and doesn't get better needs to be checked out. There are many different types of and causes of skin rashes, and the first step will be having your doctor examine it closely.
For example, eczema
is a inflammatory condition of the skin causes red, itchy areas that tend to flare up and calm down periodically. It tends to be treated with good skin moisturizing and topical steroid medications to reduce the itching.
Similarly, psoriasis is another inflammatory condition of the skin that specifically produces "scaly" areas which might be consistent with what you are seeing. Simple cases tend to be treated also with topical steroids.
Finally, certain fungal infections of the skin (ringworm) can produce scaling rashes that can be quite stubborn and persistent for a long time. Some of these can be treated with topical anti fungal medications, but some will require stronger prescription oral medications.
Your doctor can tell you which of these diagnoses (or another diagnosis) is most likely after an examination, and they can also prescribe the necessary treatments for you. Good luck, and please see your doctor soon.