This is very common around 6 weeks of age is it a pimply rash" it could be Erythema Toxicum ..doctors say leave it and it will go away if you are concerned .,and speak to your doctor for options ..good luck
My sisters dr kept telling her that her baby had eczema but it turned out he was allergic to the dairy she was consuming and when he breastfed his body wasnt able to handle it. She cut out dairy and he was a completely different child. Best solution though is call your pediatrician and talk to them because they may be able to better help you with what is going on. I am sure you have an appt coming up pretty soon for your baby anyways so you can always bring it up then if you dont want to go in sooner but without seeing what it looks like its hard to see. Baby acne though is just like little white heads and like previous poster said it will go away on its own. Good luck but best solution is at least call the dr and they may be able to tell you over the phone so you dont have to make an appt.
If it is baby acne, don't do anything to it. It'll go away on it's own.
My son had it too as a new born and his was baby eczema