Definitely stop using products you buy at the regular grocery store. I'm a big fan of Melaleuca products because they worked on my eczema (only one doctor visit in 6 years); they are affordable and come right to my door. Regardless of which products you choose, I recommend that you:
1) Get all the irritating chemicals off his skin switch laundry and personal care products (sheets, clothes, towels, soap, shampoos, floors).
2) Put him in organic cotton clothes only if possible, sometimes the chemicals in the synthetic clothing are a problem.
3) Not sure what/if he is eating anything yet, but stay all natural even if you have to make your own baby foods.
4) Eliminate any air fresheners (including lysol) and perfumes in the house as well.
5)
Once you change the things you can see how it works. If you are still having problems, I'd recommend having him tested for food and environmental sensitivities/allergies, let me know and I'll give you a referral (cause I've found a great one and had to go through some not so good ones). I can't find her card on my messy desk, right now, but will get her info if you are interested...