create a backup

[NickYOW]

i am attempting to copy only changed cell in a column and copy them to a back up sheet. this is going through every cell, I would like to only copy and past only new changes.
its take to long to run through 164 lines when only 2 or 3 Cells have been change. I using the back up, as a back up and as part of a record for a undo command. I thought if filter out the blanks, I could skip over the blank cells. here is the code i have.

col = split(activecell.address(1,0), $)(0)
row = split(activecell.address(1,0), $)(1)

Cells(7, ActiveCell.Column).AutoFilter ActiveCell.Column, "<>"

selected = Sheets(originalsheet).Range(col & "" & row).address

Do While True

Sheets(originalsheet).Range(selected).Copy

erow = Sheets(originalsheet).Range(selected).row

Sheets(originalsheet).Paste Destination:=Sheets(backup).Range(selected)

If row = 172 Then

Exit Do

End If

selected = Sheets(originalsheet).Range(selected).Offset(1, 0).Address
row = row + 1
Loop
activesheet.showalldata

very helpful people here and once again reaching out.