From the symptoms you have described, it is most likely a viral infection.
Viral infections typically last 5-7days, with the first 3 days having the most severe symptoms of fever, and sometimes cough and cold. However after the first 72 hours, fever starts decreasing in intensity and frequency.
Medicines like paracetamol can be given for fever. But since viral fever doesn't have a specific cure, goal is to keep the child comfortable and well hydrated as the body fights the viral fever.
It is common for children to get frequent viral infections when exposed to other people having viral disease.
As children grow and get exposed to more and more viruses, they develop immunity to common viruses and the frequency with which they get viral fever decreases
Next Steps
You can wait for 3 days, if the fever worsens/ new symptoms are seen, you can visit your pediatrician
Health Tips
Make sure that the child is well hydrated, with water, ORS etc. Soups, porridge, Kanji and other homemade rice based food can be given for nutrition. A little decrease in appetite can be expected, but fluid intake should be adequate.
A well hydrated child should pass urine atleast 3-4 times in 24 hours. If child is refusing all oral intake and has not passed urine for >12 hours and/or is lethargic, please visit your pediatrician