When Ayna was grabbed by Najim Choudhury, he missed the train with Hridi at Kamalapur Railway Station. Then Ayna was arrested, which had happened at afternoon, the next day. And the next shot showed that Hridi went to Ayna's place wearing the same dress and the same bag in hand from yesterday, meaning she went to his place directly from the station.
When Ayna completed the terms for the gamer boy in jail, we could see him returned to his home with a full head of hair. But due to the character he took, he needed to shave his head before. Just before the scene, we could see him in the court with an almost bare head.