The IUD wouldn't fit! questions about implanon.

Hope
Okay guys, so I was real pumped to get my Marina in, waited ages then went and got it from the chemist ect, and only when she tryd to put it in did she realise my cervix was to small! I needed it cause I'm going home for a month where my bf is in a week. 
I ended up deciding to get the implanon for the holidays and see f I wanted to keep it after that but I'm not quite sure about it. My doc put it in the underside of my arm (shown in pic) as opposed to the inside where I see most people get it, I was wondering if anyone else had it there? 
Also plz give me your reviews of the implanon (rod or nexaplon depending on where u are) kinda nervous about it. It was inserted on the 4th Day of my cycle (yesterday) and needs to be working by the 12th/13th Day. 
Yes I am aware that it doesn't protect against STDs, thanks in advance xx