Nexplanon

So I started my period today and I haven't gotten it in 2 1/2 months, and the cramps are killing. anyway, my doctor and I set up for within the first 5 days of my period I'm getting Nexplanon. I'm really scared. I'm probably getting it Friday. she said she makes an incision to make it easier to slide in to my arm, and I'm really super scared of the bruising and soreness cause I just got my meningitis shots last week and I thought those hurt lots hah.. Any tips? im expecting my period to be super irregular and long or stop all together. Idunno. I just want some help or pointers or moral support I guess.