My son appears to have bitten by something.. He has a rash on his arms and legs  bumps red in color slightly raised and very itchy!!  He appears to have bitten by something on his shoulder above his arm pit that is white in color the size of a quarter.
Hi I do care for your concern. Your history suggest of unknown insect bite. However, white headed bump around arm may be due to infection. I would advise Consulting your physician to know whether it is insect bite mark of infected bump. Regarding itching taking medicine such as cetirizine twice a day will relieve you of symptoms, in case of infection antibiotics may be needed. Hope I have answered your question, if you have more feel free to ask. Thank you.