PUS in urine test for 3 month old baby boy

Patient: My son is 3 months old, He is frequently doing urine and he’s crying when he want to pee.I did his urine test and found 4-5 PUS cells and 2-3 Epithelial cells in urine. Other parameters are NIL OR Absent.Can you please suggest is it serious and what should we do for cure ?Regards,

Symptoms: crying when want to pee