Putin is not known for his soft heart and willingness to let bygones be bygones.
I don't think for a moment that any side didn't envision this as a possibility. When you're flying sorties, there's going to be accidents. With this many borders involved and a NATO power next door, the risk only became larger. While it's serious, it's not like Russia didn't know these risks beforehand. They saw this possibility before they got involved. Doesn't mean they won't be happy about it, but I guarantee a Turkish response was at least thought about.
Of course not, that's why the Russians initially tried to deescalate by publicly attributing the downing to Syrian rebels, not Turkey; however, now that Turkey has made that impossible (for which, given the recent series of Russian intrusions since the campaign in Syria began, they had pretty strong domestic reasons), the Russian leadership's room to deescalate while maintain an image (particularly a domestic image) of strength is narrowed.
Putin is a brilliant tactician. That is why he is in the position he is in. He isn't going to retaliate against NATO for a downed jet, but I am also going to wager that at the end of all the reporting and global discussion about this incident, he will come out looking stronger. That's the kind of leader he is, hate him or love him.