White Smoke E, Losing oil, Low Coolant After Valve Cover Gasket Change

Bmw 328i 2010. E90. I changed my valve cover gasket, my car was running well for a few days. Then white Smoke started coming out of the exhaust, oil was low at 1/4, and coolant was low, it also starts roigh when when it is cold. Everything was fine before changing the gasket. My mechanic says it's fhe PVC valve and wants me to change the entire cover. But the car was fine previous to the gasket change. I used an OEM gasket.