VERY CONCERNED.

So, I know this is super weird but I'm very concerned.
I wear thongs every single day and don't think I even own different underwear. 
Today, I was looking in between my butt cheeks in the mirror because something felt like it was hurting or bare and there is like a strip of pink, bare skin right along where my thong must stay.
Is it possible that my thongs stripped my skin bare? 
How do I heal it?
Thanks.