Worksheet_selectionchange On 2 Columns

I have this code that will update column "AW8:AW60" when a date is entered into"z8:z60" if column"c8:c60" equals 4. It works great if the c column doesnt change if it does it doesnt recaluate. What I need it to do is if the number in "c8:c60" changes it recaulates.

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim msgg As String
Dim msgg2 As String
Dim NewDate1 As Date
Dim c1 As Range
If Not Intersect(Target, Range("z8:z60")) Is Nothing Then
msgg = InputBox("Please Enter A Date..." & vbLf & vbLf & "(MM/DD/YY)")
If msgg = vbNullString Or Not IsDate(msgg) Then
MsgBox "You Did Not Enter Date!", vbCritical
With Target