1. 5 year olda baby has fever. Doubts?

Hi My baby is 1.5 year old, he got fever 4 days back I gave him the crocin ds 250 whenever the temp is more than 99 with intervals of more than 6 hours.. After 2 days fever has gone... The next day he got ulcers and refuses to eat food in the same day he again got the fever here are my doubts regarding the fever please clarify. 1. If the temp is 99 or 100 can I give crocin ds Or only sponzing is ok?? 2. After I give the crocin how much time to wait for fever to come down. Why I m asking this because I gave crocin ds 3 ml to my baby I waited for 1 hours still the fever didn't come down... Then I have the meptal p then fever came down... But sometime I waited for 2 hours with 99 or 100 temp to come down completely.. So wht is the exact duration I should wait 3. When I gave meptal p after the crocin my baby temp reduced to 97.4 or 97.3 sometimes his head hand all body is cold... Is it normal?.. After sometimes like 3 hours it came to normal. 4 the medicine not going more than 4 hours