Dumb. Scratched my eye. How long till my cornea heals?

Typically, 24 hours. The cornea turns over new cells every 24 hours, so typically a scratch will heal withing 24-48 hours, depending on how deep the scratch may be. You also need to be concerned that there is still not a foreign body present in the eye or the eye becomes infected. If your vision is affected, the pain increases, symptoms not improving, the eye is getting more red or is matted in the am, see your doc.