I have gone through your post in which you have mentioned that your son is suffering from Nephrotic syndrome
Nephrotic syndrome is a condition in which there is kidney
damage causing Proteinuria
(loss of proteins through urine)
This results in Hypoalbuminemia
(decreased protein levels in blood)
Hypoalbuminemia reduces the serum oncotic pressure leading to fluid accumulation in the interstitial tissues, which manifests as puffiness around eyes, swelling (edema) over legs, etc.
The mainstay of treatment is by administration of glucocorticoid, which acts as an anti-inflammatory and immunosuppressive agent for treating the condition.
So...it will be better to consult a Pediatrician
& start treatment.
Long term use may have side effects like increased susceptibility to infection, easy bruising, abnormal fat distribution in body, etc.
Symptoms aggravate if medication is stopped abruptly.
Make sure while discontinuing the medication, its dose should be tapered gradually instead of stopping it abruptly.
There is nothing to worry...after completion of treatment, your son will be alright.
Wishing him a good health.
Thanks & take care.