The question is as simple as the title. Did Luther have a minor alteration in his view of Mary, or a major one after being born again?
Note: By the way Luther did use the term 'born again' for some reason people think it is a new term.
Originally Luther loved to pray to Mary:
“I chose twenty-one saints and prayed to three every day when I celebrated mass; thus I completed the number every week. I prayed especially to the Blessed Virgin, who with her womanly heart would compassionately appease her Son. (Luther's Works V54.340)
After being what he called born again, which is often referred to as his Tower Experience, he began to see Mary as someone the church used to commit many blasphemies in holding idolatrous esteem of her:
I was as deep in it as all the rest, that we were plainly taught to hold Mary in Christ’s place and office. We held Christ to be our angry judge and Mary to be our throne of grace, where all our comfort and refuge lay, if we did not wish to despair. Was that not a horrible innovation? Where were the bishops who rebuked such new blasphemers and betrayers of Christ who took away Christ’s office and gave it to Mary, who taught us to flee from Christ and fear him as a whipmaster, and directed elsewhere our confidence which we owe to him as the true divine service? We have learned nothing but idolatry from these traitors! (Luther's Works V34.27