Combining IF With LEFT To Hide Columns VBA

I'm trying to write some code to Hide columns if the first 3 characters of cells in a range equal the contents of another (formula equivalent would be something like this =IF((LEFT(A2,3))=A1,"HIDE COLUMN", "SHOW COLUMN"). I have gotten this far but cant get it to work;-

Private Sub Worksheet_Change(ByVal Target As Range)

Dim r As Range, cell As Range

On Error GoTo ErrHandler
Set r = Me.Range("B7:CG7")

Application.ScreenUpdating = False
Application.EnableEvents = False

Row = 1
col = 1

For Each cell In r
If cell.Value = "" And Left(cell.Value, 3) = cell(Row, col).Value Then
cell.EntireColumn.Hidden = True
Else
cell.EntireColumn.Hidden = False

End If

Next
ErrHandler:
Application.ScreenUpdating = True
Application.EnableEvents = True
End Sub