Decreasing CRP along with clinical improvement reassures both physician and parents. There is nothing wrong with repeating it

CRP is a sign of infection or inflammation. If there is any persisting signs of infection, like fever,dull activity, poor feeding and so, it is better to recheck to know if it’s still rising after a period of few days. Should not be really relying on just investigations, sometimes clinical symptoms also will point out the doctor to redo the test if needed to confirm the diagnosis.

Tests are done only if there are symptoms and signs. If he is active, no need to repeat

Give 7 days

Need to complete 7 days course, then consider

CRP takes time to decrease, you can go for procalcitonin and platelets counts