Period on nexplanon

Hey.! So I am on nexplanon and I just got my period after 4 months. My period has been very light flow but it’s just a dark brown color like it’s just old blood coming out. Recently I have been having a little itch down there and i dont know why. I have no yeast Infection. No chunky discharge. Is it just because its old dry blood coming out ? Is it normal to itch a little.