My skin was very cooperative throughout the last weeks. Just a few days after I filmed my First Impressions video on the Dior Diorskin Perfect Cushion Foundation (what a name!) it decided to act up. It was turning from well-behaved to oil slick, from pretty clear to full of breakouts and then, within 24 hours, to dry, itchy and flaking.     That of course had nothing to do with the foundation, I blame it on the change in weather we experienced, but it gave me the opportunity to really…