What does the verb tense change signify in line 87 of "The Love Song Of J.Alfred Prufrock" by T.S.Eliot?

It may signify that Prufrock's emotion has changed, from where he is portraying his emotions on his past, his achievements and how time is going so fast, each day that passes Prufrck is getting older and older

Though I have seen my head (grown slightly bold)

and fearing of death-(refering back to Dante's extract) Prufrock fears of his fate in death weither he is to suffer in an internal torment.

To where Prufrock's emotions changes to questioning himself to take a chance to re-lit his achievements and having no fear of death, believing that he can live again after death, if not conquer death, conquer his fear (Eliot show this using the reference of Lazarus).

To say: "I am Lazarus, come from the dead"

Hope this helps a little bit.