If your baby’s fever returns after a few days, it may be caused by an infection. Although the baby has been well for a few days, but the body’s resistance has not returned to normal, the body is still relatively weak. If a viral or bacterial infection occurs, it can easily lead to another fever, so you need to take your child to the hospital to check the blood count and C-reactive protein, and preferably check the Mycoplasma pneumoniae antibody. If Mycoplasma pneumoniae antibody is positive, the fever is often caused by mycoplasma infection, and azithromycin should be used to treat the fever. If there is an elevation of white blood cells, accompanied by an elevation of C-reactive protein, it is often a bacterial infection, and the baby needs to be treated with antibiotics, such as pediatric cefadroxil granules, amoxicillin clavulanate potassium. If there is allergy to the above drugs, azithromycin can be used for anti-inflammatory treatment. In addition, if the body temperature is relatively high, above 38.5 degrees, you need to give your child a fever-reducing medicine at the same time, such as acetaminophen granules.