Bad news: you can't unread things.
Good news: with just one crisp piece of paper and two quick motions, you can prevent yourself from reading unpleasant things, possibly forever!
An optometry student I know says they're unaware of this occurring, as the eyelid will generally catch the bite. If you did get a bug bite on your eyeball, first thing might be cold compress and antihistamines for the swelling and irritation.
When I was in middle school, a girl did in fact get a bug bite on her eyeball. It was blood red for a week and she couldn't see well, but long term she was fine.
Most likely the eye wouldn't work anymore, or work too well as all the light gets in. What I do know is that impact and even injury to the eye can have drastic effects on both the way the eye works and how your body responds. My dad got hit with a screw in the eye and he still has it, but got bleeding behind the eye and nearly lost it.