How can I exclude a range of cells from having the MsgBox warning pop-up

I have the following vba code in excel that pops up a warning msgbox if a user tries to enter data in these 2 cells (Columns L & M) and there is nothing populated in another Column.  The problem is the msgbox should only pop up if the user is selecting one of the 2 columns (L & M) starting on Row 8 and below.

Code:

If Target.CountLarge > 1 Then Exit Sub

If Target.Column = 12 Or Target.Column = 13 And Target.Row > 7 Then
   If Cells(Target.Row, "F") = "" Then
      MsgBox "You cannot update SubmittedDate or Comments2 because this Invoice has not had an eBill file generated yet.", vbExclamation, "InvElecHistoryID Missing!"
'      Cells(Target.Row, "F").Select
   End If
End If

Select allOpen in new window

How does the code need to be changed to adapt to this?

Thanks,

gdunn59