Dry skin that even aveeno won't help?

I occasionally suffer from dry skin but it is never sever and I usually just slap on at bit of extra moisturiser, but about three weeks ago I started to get REALLY dry skin. I purchased aveeno because I was told that's really helpful for dry skin but it just keeps getting worse and worse and when I put make up on my skin looks gross and scaly. I always drink lots of water and exfoliate once a week. How can I get rid of this dry skin?