How would i know if the nexplanon is inserted correctly and also working correctly?

Go see your doctor: Check out http://www.Nexplanon-usa.Com/en/consumer/about-it/q-and-a/index.Asp. "if you and your health care provider cannot feel the Nexplanon implant after insertion, you will need to use a non-hormonal birth control method (such as condoms) until your health care provider confirms that the implant is in place." once inserted, it starts working immediately although its effectiveness can be altere.