It is possible that your son has a virus infection such as Roseola. This does not appear to be an allergic rash as the rash would be very itchy and he would scratch a lot.His rash should fade within 2 or 3 days.
He also appears to have what is called a BCG abscess which developed in a lymph gland above his collar bone. This kind of abscess takes many months to heal and to disappear. Treatment is not usually recommended but if the lump is discharging or becomes bigger you should return to your paediatrician for an opinion.
The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal
advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.