I don't fool with comments much, but I did have a program update comments once, long ago. Let's see, here....

Well, it looks like all you have to do is look at the Comment property of a given cell. If there's no comment on that cell, the Comment property is Nothing. If it's not nothing, then you can look at Comment.Text to see what's in it. That's not all there is to comments, of course, but maybe that's all you need to get started.