As a mother of two (now grown) children, I can empathize how badly you want to help your son. Below is a protocol for external use of Miracle-Mineral-Supplement - I'm not sure if I found it on the curezone site or on Jim Humble's site. It can be a starting point for you, and I think it will work nicely.
Use Miracle-Mineral-Supplement for healing sores, burns, wounds, psoriasis, eczema, cancer, ringworm, acne, rashes, staph infections, athletes feet, and a hundred other problems of the skin. In order to do this follow these instructions: Obtain a 2 ounce mist spray bottle. Most drug stores sell empty spray bottles.
Put 20 drops of Miracle-Mineral-Supplement in the bottle and 100 drops of citric acid and swirl to mix, wait 3 minutes and then fill the bottle with water. You now have a spray solution that is equivalent to 40 drops in 1/2 glass of water in strength. This solution stays fresh for about 3 days. The reason it stays fresh for that long is because of the strength. Once it is diluted in the body it rapidly disintegrates. Or on the skin, it disintegrates as it dries.
Once you have made your solution, you should spray any sore about once an hour or every two or three hours all day long. Allow the solution to dry on the sore. In case of a rash, spray it on the entire rash. Rinse off with clean water in the evening before bed, dry, and re-spray before going to bed. In case of babies under 2 years old I would suggest that you dilute the solution at least twice or start out with only 5 drops of MMS instead of 20.