No need to Set
Private Sub WorkSheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
If Not Intersect(Target, Range("$B$6:$B$22")) Is Nothing Then
Set c = Worksheets("Comments").Range("$A$2:$A$500").Find(Target.Value)
If Not c Is Nothing Then
c.Offset(0, 1) = c.Offset(0, 1) + 1
c.Offset(0, 2) = Date
End If
End If
Cancel = True
End Sub