Dear K.,
I am not a doctor but have quite a bit of experience with the medical field and with kids in general. As a health insurance agent, I have seen and heard just about every possible malady you can think of.
What you are describing does not sound like warts. There are many different types, but they generally tend to be growths that are on the surface of the skin. On the face, hand or arm, for instance, they tend to look raised, bumpy, even kind of scaley. The don't tend to have pus, as they are more of a fungus as opposed to something that involves the sebacious glands. It sounds more like your son has clogged pores. And, he is about at the age where this could start happening as a result of his change in hormone production. The first thing to do is to gently wash the area with a mild, non fragranced soap and allow to air dry. Do NOT scrub with a washrag, etc. Even just with clean fingertips, VERY gently. After the skin dries and is allowed to breathe a little bit, I would put the tiniest little dab of neosporin to combat any bacteria. Whatever you do, avoid irritating the spots any further. By all means, get your son in the habit of never touching his face without clean hands. (I have a son and their little hands get all kinds of bacteria on them). Try these things and see if it helps. I don't know where you live, but I can guarantee that your county health department has clinics for check ups and immunizations, etc, for kids with no insurance and they charge on a sliding scale. You can get both of your children taken care of there while waiting for your insurance. That's where I took my children when I was going through my divorce and they were AWESOME!
The other thing you should check into is the Healthy Families Program. It's excellent and inexpensive coverage for children in qualifying families. It's not medi-cal, in fact, you have to make ENOUGH money to qualify. It is definitely worth looking into. Almost all pediatricians accept it. For two kids, it might cost $20 a month. Even surgeries, God forbid, are paid for.
Look into it and take care!
Take care!