Seriously, I don't think dermabrasion can hurt unless you sand too much off and feel pain, or you don't use sunscreen and hang around outside a lot. It gets rid of a load of dead cells and massages the skin, increasing circulation.

Dead skin cells don't come off until you rub them off or do something similar. Faces don't see that much action, so the cells tend to accumulate, even with washing. If dead skin is just falling off your face, you have face dandruff and something really weird is going on. It's worse in the winter for me. I think my skin is trying ot overcompensate for the dryness and coldness of the air, but maybe I just notice it more. I'm starting to love hot, humid summer days...