Why isn't this code looping through all the sheets?

This code will work on whichever sheet is currently active, but will not continue on to loop through ALL of the sheets. I can't figure out what's wrong. Does something else need to be initialized? Thanks for any suggestions...I'm pulling my hair out!

Sub Fill_Zero_if_HasBorder()

Dim my_range As Range
Dim my_sheet As Worksheet
Dim c As Variant



For Each my_sheet In Sheets

Set my_range = Range("A1:CA200")


    For Each c In my_range
    If IsEmpty(c.Value) = True Then
     If c.Borders(xlEdgeTop).LineStyle <> xlLineStyleNone Then
        If c.Borders(xlEdgeBottom).LineStyle <> xlNone Then
            If c.Borders(xlEdgeLeft).LineStyle <> xlNone Then
                If c.Borders(xlEdgeRight).LineStyle <> xlNone Then
     
     
     c.Value = "0"
     
     End If
     End If
     End If
     End If
     End If
     
    Next c
 Next my_sheet
End Sub