Hi, This is for sure that dulcolax suppository is not the culprit for fever. But fever can be due to various reasons. Please document the fever. If it is 100°f or more, do give syp paracetamol in proper doses. Cold sponging the body and forehead would be helpful to bring down fever.
Next Steps
If fever is persistent for more than 48 hrs, do visit a pediatrician for clinical evaluation and workup.