What are some medications to treat chronic red and dry/flaky skin?

Several. It depends on the cause of the dry skin. Moisturizers, steroids, antifungals and others are all potentially helpful depending on the cause.
Depends. Depends what you mean "chronic red and dry/flaky skin". You may have eczema which needs help from dermatologists not yourself. If it's simple long term dry skin problem, then moisturizers like nivea creme, cetaphil, aveeno, (oatmeal) eucerin, cerave may help.