Hi, Welcome to Health care magic forum.
It appears to be the pain due to infection, may be due to the scratch,insect bite, or a blister
The treatment remains the same what ever the reason is. I advise you to consult a pediatritian for diagnosis and treatment.
I usually prescribe to my patient with such symptoms ofloxacin
syrup, and mefanamic acid syrup.
Give him more of green leafy vegetables, pulses, sprouts,and
protein rich foods to hasten the recovery.
Wishing for a quick and complete recovery. Thank you.