Thank you for your query,
your child is having is because of post vaccination
with the booster of DPT-Hib.
And the fever may last for two to three days, nothing to worry.
syrup as advised by your doctor.
If any associate issues like cold, cough or throat pain then we may think any other associated infection.
Consult your Pediatrician
if fever persists beyond 3 days or any other problems develop.
Hope i have answered your query.