What can i take for extremely dry itchy skin? supplement, medicine wise. kind of hard to cover my entire body with lotion.

Actually you should: cover your body with lotion especially after bath or shower when skin still wet. Also add a moisturizing body wash not soap. Add oral Vitamin E and B complex for skin

Have thyroid checked: Have you had your thyroid function checked? You should talk to your doctor and rule out any medical conditions that could be making your dry skin worse.