Water painting tips?

I messed up my skin color when I was panting and I was wondering if there's any way to fix discolorations when you water paint.

It really depends on the water paint ingredients. First, try warm, soapy water. Other things to try are olive oil/butter/mayonnaise/etc. Let it sit for several minutes then wash off. If that doesn't work, try rubbing alcohol. It that doesn't work, then wear your creative badge with honor. It'll wear away in a few days.