Hi,
Congratulations on the fact that you are a parent!
To answer your question,I believe your son might be having normal newborn rashes, medical we call it fancy as "
erythema neonatorum" . I would however be able give if I had a picture of the rash, watsoever, you seem an informed parent assessing the baby's general condition being good. Given that case, just a few things to look into:
1.Newborn rashes should start reducing by 5th week, so look for if its regressing.
2. Feel for the rash and make sure, the are not bumpy and flushed with the surface
3.Apply fine layer of oil of your choice to open the pores.
4.Keep a look on general being of the baby, as in how active,feed, the urine and poop counts.
5.If you feel something is abnormal/ rash is increasing, better get it checked.
Hope this helps.