Debug Assistance - Auto Date Entry

i try to lock cells in the area the VBA code affects. My goal is to actually have affected cells by this VBA code lock immediately after anything is entered in the affected cells. Area needing Debugging is in the If - Else portion. My worksheet will be protected.

Private Sub Worksheet_Change(ByVal Target As Range)
Dim LLoop As Integer
Dim LTargetRange1 As String
Dim LDestRange1 As String
LLoop = 10
While LLoop <= 1000
'Link column B to A
LTargetRange1 = "B" & CStr(LLoop)
LDestRange1 = "A" & CStr(LLoop)
If Not Intersect(Range(LTargetRange1), Target) Is Nothing Then
If Len(Range(LTargetRange1).Value) > 0 Then
Range(LDestRange1).Value = Date
Else
Range(LDestRange1).Value = Null
End If
End If
LLoop = LLoop + 1
Wend
End Sub