I need help with my dry frizzy hair?

wen i take a shower every other day after the shower i gently brush it out and let it air dry and after it drys its all dryed up and frizzy it feels like a barbies hair (plastic) but wen i forgot to take a shower for 4 days it didnt stink or nothing it smelt good my hair was smooth and shiny and no frizzy or dry but it did give me acne from the greasyness and oils in it plz help me i dont want acne but wen my hair isdry my skin is clear