Help! not sure if this is an issue

So I'm 14 years old and had my period for approximately 6 times and so is becoming more regular. Anyways, my cycle is almost done and I think tomorrow will be the last day. Out of curiousity, I ripped open the back of the pad with my light flow and saw a bunch of reddish brown crystal-like dots. It was a dry pad and a little older. I'm really confused and a little stressed that it might be serious. It probably isn't but a still worried. Help!