Hello my guinea pigs eyes are watering and I was just wondering if that is bad. They have been watering for a while now :( then it goes hard.

Well have you repainted any rooms or recently moved the cage to a new room? Contact me back please. Paint can kill a guinea pig! Happened to me. :((((

Oh also what bedding do you use because the wood chips make their eyes irritated

As Ela2219 said bedding could cause it or if it's a milky white (crust) that's cleaning it's eyes it especially sometimes happens when getting a bath