My oldest son got that stuff in his eyes once. He was freaking out. We had to turn the car around and go home, and he laid on the bathroom floor while my wife poured water on his face. It wasn't funny at the time, but it is now! haha
I know you saw my new user info post already, so I won't share it again. Welcome!
I felt so horrible doing that, and in my first week as a teacher. I can imagine your son freaking out. I had a student, a few years ago, get some bleach on their finger....you would have thought they were dying!