Some parts of my body skin is dried and seldom itchy. so i have dark patches. it aggravates when i sweat. i apply diprosone (betamethasone dipropionate) on them from time to time.?

Try hydrocortisone: This sounds like you have what is called "seborrheic dermatitis". What a big word for something so common! it is in the eczema family. Try rubbing baby oil into the area while the skin is soaking wet after showers then towel dry. There is no cure for this, it will almost always come back. Don't get discouraged, just keep the diprosonebbb handy.