My PCV is toally dead...It was still ok last month when I checked it, but now, the hose is mashed and the nipple is gone as well. Perhaps I've already driven in this condition for several days...Is there going be any harmness to the engine other than oil leak? Can I still drive it?

Mine was held together with e tape for a while. You dont need the PCV valve stuff at all to drive. In fact, its better for a turbo engine to have a filter instead of the direct return.

However, you should do something about it to avoid spewing oil around your engine bay and the atmosphere.