Doc could not locate implanon and left it in. he also put nexplanon in. what concerns she i have with it still in?

Should be removed: The manufacturers are absolutely adamant about having the devices removed once they have expired. There is the (rare) risk of it migrating into a muscle or other organ. The nexplanon's can be identified with sonographic evaluation (certain wavelengths are necessary) -or with mri. You may want to get a second opinion, and see if you can have the ultrasound done to locate the Implanon then remove.