Thank you for your query on Healthcare Magic.
It is looking like an inflammatory rash
because of a virus or an allergic one.
As it is associated with cry, it requires examination by the pediatrician
Is there any tenderness to touch?
Is there any restriction of limb movements?
Check for his body temperature.
Consult the pediatrician for physical examination to find out the reason for this and its appropriate management.
Hope I have answered your query.