welcome to hcm forum
as per your clinical presentationi would like to know where the lymph
nodes were enlarged inj the leg or somewhere else, i would like to know after the treatment by DR. whther your son was symptoms free or not and also to know whether the blood which were abnormal became correct or not. this all is require to know whether the present knee pain
is related to it or not.
if it is not related to it then pain around the knee in 15 yr boy we have to rule out os ggod schatter disease or stress fracture
, tumour. for this you can meet an orthopaedics who will examine and advised for the xray aand mri
and treat accordingly mean time you can take rest and analgesics which will reduced the pain.
so need not worry do ahead with the test once the report is reay meet the orthopaedics who will reply to all ur querry.
wish you good health