I got a drop of listerine in my eye. i immediately rinsed it, even though i had no burning or irritation, but after rinsing it, the eye got red. is that from tap water or from the mouthwash?

Mouthwash is formulated to be used in then mouth, not in then eyes. Probably irritation from the alcohol or other chemicals in than mouthwash. Should be transient. If it worsens, becomes irritated, weepy, exudes a discharge, seek evaluation by an Ophthalmologist.

Could be a combination of both liquids. Did the redness go away. Probably, only a minor irritation.