After Damu Anna went to Shirdi in person, did Sai Baba change his mind and finally give him permission to proceed with his plan to earn millions?

No, the source material indicates that Sai Baba did not change his mind, primarily because Damu Anna never gathered the courage to ask him again in person. Following the disappointing written reply, Damu Anna was advised in the letter to visit Shirdi, which he did. As Chapter 25 narrates, he traveled there with the hope that Baba might give him permission. However, upon arriving, he "sat near Baba and prostrated himself," and while he massaged Baba's feet, he ultimately "had no courage to ask." The account ends there, showing his hope was not realized because he was too hesitant to bring up the matter again.