Thanks for posting your query on Healthcare Magic
small swelling below the ear could be palpable lymph
node which may be normal in this age group.
Pain and increase in size in lymph node can happen with infection of ear, may be otitis media
or otitis externa
Your child's hemogram is within normal range, your concern low hemoglobin
may be due to reference rage give by laboratory. It can be low high monocyte
count require work up.
If you find swelling is tender, red and increasing get an opinion from pediatrition.
Hope you find information useful given by me.Take care.