Nexplanon

Ana

I’ve had the nexplanon since August of last year and I got a period in September I can’t remember exactly when but recently since January I’ve getting like this dark brown discharge that hasn’t ceased and I was wondering if this was common with Nexplanon or if I should talk to my doctor about it because when I first got my period in September it started out like dark brown and then turned into a regular period? And I wondering if it’s just old period blood making it’s way out or if it’s an underlying issue?