
WHAT HAPPENED TO DOOSHIK? WHY DID HE SWITCH SIDES??

Are you talking about one of the twins?? He most likely thought that would be the best way to get revenge. The twins help record the rape of Jooha. So Dooshik was probably thinking that the best way to get revenge was doing the same thing to hurt the twins in the worst way possible, just as they did Jooha.
does this mean jaeshin's puppy era is gone?
no, he became a puppy again at the end of chapter 65.
Lee Nok is still not in love with him, he just likes him.
In theory this is what was written in Korean at the end of season 2, but it was translated differently in English.
Poor Jaeshin.:(
Noo. Jaeshin asked "for the things to not change", to go back and still turn into Geumdong during the day. In the afterworld the one with a veil on his face guessed it's because Nok really likes "this little one" :3
Although you're right it was literally "I like you" but in Korean (Japanese and Chinese too) it "counts" as a confession. Just a cultural thing.
Also, don't you think Jaeshin is rather content with it? In ch 63 he says "the one you like (*love) is here" (so don't look at the ones who scare you). In 65 he wonders when Nok's started to have feelings for him and wants to hear the confession again. If it wouldn't be enough he would be like "why don't you love me more?" "what more do you need me to do?" "aah dammit!" :P
oh i'm sorry, then I misunderstood!