I rented a disc today and there is a stain from a liquid on the disc art. I can't really tell if its on the data side of the disc too. Can this in any way hurt my dvd player? I know this may be a stupid question, but I wanted to ask before I put the disc in my player.

If it's not actually wet, then no, it won't harm your player.

That's why I buy adult DVDs instead of renting.

DJ