I was putting gasoline into a mower last night and it splashed back out like a fountain and hit me in the face and eyes. There was some old gasoline in the mower and the gas in the can was from last fall. I rinsed my eyes out with water for 20 minutes and think they are OK, but don't know what to do about the mower. I never knew something like this could happen.
Don't think the old gas in the mower nor the gas in the can had
anything to do with the splash-back.
Whatever you did to cause it needs to be addressed.
More details would be needed to help you avoid the same happening again.
Avoid pouring so fast, or avoid having face in path of the splash.
Your eye rinsing was a good plan and hope you can find a better way next time.. Albeit, fresh gas is the way to start the season.