It happened to someone I know called Arthur Itis.
stop randomly bumping you've caused a nerve to juggle out of place and get attached to your cornea
Thing is it'll dull down after like a minute, but the nerve will be over sensitive for a long while afterwards, and it can happen in chains.
Once I put my finger in Night Fox's star fish and its teeth randomly bit down and drew blood from my finger.
Is that all? That's nothing on what happened when I did it.