It is usually caused by a baby's sweatglands still being plugged up with a waxy build up. Yes it should clear up in a couple wks.
My friends baby had that..can't remember what its called but the doc said it goes away within 2 weeks and some days its worse.then others
My baby girl had something similar...it actually turned out to be neonatal lupus. I have an autoimmune disease and it can occasionally be passed to the baby. But the good news if it is that is its temporary! Its goes away at around 6 months. Good luck.
if it was just on his face I would say that thats pretty normal, its usually from the rush of hormones they get at birth, he may have caught a little infection from the hospital, I would get them checked out just to be sure, but I dont think it will be anything to much to worry about