Awww....poor Dozer! First of all, give him a big hug for me. Secondly, I would give it a day to see if his eye gets better. Is there any gunk coming out of it? If you have some saline maybe you could try flushing it out. ( I know, easier said than done!) If his eye was red from hitting his head, it would prolly just be a broken blood vessel and would not likely cause him any discomfort. He maybe scratched his eye or has an infection. Eyes have a tendency to heal really quickly. If he did scratch it, it should be much better by tomarrow. If it's no better, call your vet. Best of luck. 
