Ok, seriously though. How did Thor get better? 15 words or less. I don't really care that much but gimme something. Dude died. Now he's alive. What's the deal?
Might as well post it here too, since this is more the place it belongs:
Karnilla worked some magic mojo to take advantage of his death by wiping his memory from everyone's minds and replacing him with Tanarus, who was actually Ulik in disguise. She had formed a pact with Geirrodur, the king of the trolls, to use Thor's death against the Serpent (which was prophesied, remember, so everyone knew about it) as their means of finally taking revenge on Asgard. So Thor goes to where forgotten gods go, which is apparently a long-ass line being marched into the Demogorge's mouth to be consumed.
Kid Loki, however, has a vague notion that something's not right and, upon investigating, starts remembering Thor vaguely. Thor himself starts to remember who he is in the death line and starts to realize he doesn't belong there. His memory's slow return also makes Mjolnir return to him, which completes his memory. He inspires two other forgotten gods to have faith in themselves again and they begin to remember who they are too. One turns out to be a war goddess, who helps Thor bust out of the line to the Demogorge. Thor fully remembers who he is by then and they head for Earth.
Heimdall also starts to put the pieces together and eventually confronts Tanarus. They fight and Heimdall smashes the magic pendant that was disguising Ulik as Tanarus just as Thor and his two new space-god friends arrive. They have a big fight wherein Frigga f***s Karnilla up, Thor straight-up kills Ulik like he's a speck of dust, and the other Asgardians beat Geirrodur and his troll army. Karnilla and Geirrodur are magically imprisoned in Ulik's skull somehow and that's that.