Neck lines

I'll post this in facial care, as well.

I'm in my mid-teens, and I'm not fat at all, but I do know that I have lines on my neck. It's hard to describe them. When I was younger, I was very thin, but I still had these lines on my neck. They aren't a medical problem or anything - more like a cosmetic issue, I guess.

I just want to know how I can get rid of these lines because they sort of make me look fat. When I lower my head straight down, skin 'pudges' out where the lines form. I'm sorry I can't give a clearer description of it.

Is there any way I can get rid of these lines without plastic surgery or something? Thanks!