Fever itching. Blood test indicates?

My son had measles kind of rashes along with fever last month. Fever and rashes gone within 3 days but exactly after a week he started itching. He itches head, hand and leg. He is having few boil kind of rash on hand and legs at present . I noticed lymph node little prominent all of sudden on his neck.I took him to paediatrician. Doctor adviced banocide syrup and montair lc for a week. His itching reduced little bit but not completely. I have appointment next week. Before that I googled and got scared. It shows lymphoma. If there is itchy skin for no reason with lymph node swelling. Earlier i took blood test which shows reactive lymphocytes and counts were normal. I'm totally scared. Pls help me out. Is it possible for itchy skin after fever?can child get measles after MMR vaccine? What blood test indicates?