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Does his eye look like this:
I am so sorry your boy is hurt. If the eye is injured and the cornea is scratched he needs to see a vet ASAP or he could lose sight.
However, if it is just an infection or the third eyelid, you can wait.
You may be seeing the third eyelid which appears in times of pain, stress or illness.
It may be an infection:
For the eyes get Terramycin ointment. some pet supplies have it but call first or order from http://www.revivalanimal.com/
Apply a damp teabag today for 30 seconds 3 times.
If he develops any colored mucus that means the infection has turned bacterial and will respond to an antibiotic.
Please let me know how he is feeling. If you get worried I will always be here to help further.
I hope he feels better very soon.
Here is info on horners which often resolves on its own:
Good luck with him,