I think it is good that he ate and I don't think canned food will hurt him. I would try tempting him with the boiled chicken like Jen suggested though. It is good that he is drinking fine. You need to watch him carefully though if he isn't eating because the hypoglycemia/low blood sugar is dangerous!
You care about him so much and I feel like I've been in it with you since the beginning! You really are a loving parent. <3
I just wanted to make sure you got some advice so I PMed Jen because she is more experienced than me. I hope Ritz is okay! I would definitely take him to the vet if he doesn't get back to normal, or if he takes a turn for the worse tonight rush him to the emergency vet.