How can you tell that Scrooge has begun to regret being so cold to other people?

(A Christmas Carol: Stave Two)

Scrooge goes through a catharsis - he manages, just in time as far as his age is concerned, to reinvent himself. He goes through an 'enlightenment' when the ghost of his old business partner comes back from the dead momentarily to tell him about the shackles of sin (greed, selfishness, uncharitable behavior, avarice and general penny-pinching meanness) and where it has led him in the afterlife. It has brought him nothing but misery - but Scrooge can avoid it if he manages to mend his ways before his own death. This requires remorse, sorrow and genuine shame on Scrooge's part. At first he doesn't seem to be learning any lessons - then there is an illumination (he asks what will become of Tiny Tim and now seems to genuinely care.) The change in Scrooge is a change of heart.