My 5 Years Old Son Is Having Fever Between 100

My 5 years old son is having fever between 100 to 100.2 since last 4 days .when I give crocin Ds 5ml fever reduces after some time.but again fever comes after certain hrs.his weight is 14. He is active by watching TV. When he is hungry he eats and i don't force if he says no.he also drinks water.pl help how to stop fever then I. Can take out some of his test.pl advice in a very clear and simple way. Thank you. God bless you.