Ibuprofen should not to be given to infant. You should measure temp by thermameter and make a record. Best drug for infant is patacetamol . it should be given 6- 8 hourly in adequate dose which is decided by wt of the baby. Another best way to reduce temp is sponging by water. One more thing is fever is just a manifestation of underlying disease , it us not sufficiant to treat only fever. Proper general physical examination , systemic examination along with investigation should be done to find out underlying cause and treat accordingly. So you should go to your paediatrician. In case of infant it is nesassary to monitor the growth by recordind wt and height. Also take care of food and hydration