Thanks for posting your query.
Megamox is an antibiotic containing Amoxicillin
The fever that you have is probably due to the infection. It is not a side effect of Megamox.
The common side effects of Megamox are nausea, diarrhea, rash, neutropenia
Continue taking the antibiotic as advised by your doctor to get over the infection soon.
You can take T.Paracetamol
500 mg twice daily after food for two days for the fever.
Wishing you good health,