About 3 Years Ago I Noticed That I Had What

About 3 years ago I noticed that I had what looked like a line on my left hand upper forehead just below hairline.it was noticeable to my eye. I touched it and it felt like an indentation and run down to my eye brow and up into my scalp. It felt a bit weird.i didn't really think any more about it and thought it was something everyone had.the other day my friend noticed it and we started talking.no one else I know as this.should I be worried?