Frankly last night I almost thought I'd lose him, for the small animals like rabbit eating nothing means just one thing. So I gave him some water and food almost forcibly. But this morning he didn't want to eat his favorite dried food nor other "treat", I prepare for the worst. So I called to the office to take a day off (nobody knows how I would handle all those works I've left in the offfice...) and stay home to look after him. After relaxing on my futon for hours he ate some food, I even forced him to eat grated green vegetables. In the afternoon I took him to the vet, he showed me how to give him liquid food when he doesn't eat ordinary food. When we came home in the evening and I saw Mr.Uma threw himself down on my futon very comfortably I was really, really relieved.
I'm still not completely relieved, this inactiveness seems to be caused by the malocclusio, and he is an old rabbit. I'll keep my eyes on him carefully for a while. But... yes, this was a quite worrying day! And I can't say how I'm thankful for his recovery.