WHat is going on here

After finishing the book the ballad of the sad cafe i was so confused. THe ending had such a twist on it that i couldn't really wrap my head around it. Lymon completely turned in the book and i couldn't keep up with who's side he was really on. on page 46 when marvin first gets dropped off into town it seems that Lymon is shocked and somewhat appalled that marvin is back it described him as very pale and as soon as marvin turned away he started to follow him which i thought was odd. i'm also curious about the line that they looked at each other as 2 criminals who knew each other would. That is some foreshadowing right there. As lymon begins following him its almost like he is stalking him to mke sure he doesn't take over his territory, while then later in the book he helps him out in the fight despite all these negative feelings they are putting on him throughout the story.