Nexplanon

Hey, so I got my nexplanon nearly 3 weeks ago and it’s been fine so far but tonight I noticed it’s making my arm have a really weird sensation I’m not sure how to describe it, it’s like the feeling you get after you get the shivers but all in my arm, it kinda feels when someone tickles the back of your neck, im not sure if it’s hormone release of my body rejecting it or just simply my body still healing and getting use to it? Anyone else experienced this because I kinda feel like I should be worried?