Being in the country, I have trouble every year with poison ivy, mosquito bites, etc... I use vinegar or baking soda & water or dawn dish soap. Cigger bites are parasites and need nailpolish, or similar, to deny the "egg" oxygen, I don't know if dish soap will work. Also, I use a product that used to be called Rhuli gel, by J & J. (clear & green tube)that works better for me than benadryl.
OTC med. companies are trying to protect themselves from lawsuits and if used sparingly will work on children. Remember Icy Hot? Girl went into hospital because she used it every day and had to be "de-toxed". So for whatever it is worth: use common sense, observe your son, and rotate what you use to see what works,
Blessings!