You have ReviewTextLabe for each item in DataList correct?
If so then do that finding label inside DataList ItemDataBound event like:
protected void ReviewDataList_ItemDataBound(object sender, DataListItemEventArgs e)
{
Label ReviewTextLabel = (Label)e.Item.FindControl("ReviewTextLabel");
if (ReviewTextLabel != null)
{
//Do your work with ReviewTextLabel
}
}