Thank you for your query on Healthcare Magic.
The swollen lymph nodes
could be due to some infection in the past or at present in the scalp
like pustules or pyoderma
Nothing to worry and be in regular follow up to know any increase in the size as your Pediatrician
Is your son a preterm child?
If your child is a preterm child specific growth charts should be used for weight and height plotting.
Your child weight and height are lower side and but nothing to worry and consult the GI doctor as advised.
Hope I have answered your query.