You don't need different products based on curl pattern but you might need different treatment if the areas have different porosity, one is more dry or damaged than the other. If the back of your hair is frizzy that could be not enough moisture, product build up, not using enough styling products or how you wash or dry your hair.
What is your routine at present and do you know what your hair properties are?
2a-2c, medium texture, porous/ colour treated. Three years CG, growing out mechanical and chemical damage = breakage and very high porosity. Past armpit length heading for waist.
Treatments: Komaza protein, Komaza Matani, coconut oil with sugar syrup. Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume
Styler: Umberto Giannini jelly, Boots curl creme, Rockin RInglets
Experimenting with: Mega-Tek, Curl Harmony reviver, Elvive Full Restore 5.