4 yr old tested positive for influenza! started tamiflu, (oseltamivir) day 2 seemed normal but spiked fever at night! what can i expect from here?

Tami-flameout: Tamiflu is just OK and not a miracle drug. It has been shown to slightly shorten the course and severity of the flu, but not in everyone. It doesn't have a lot of bad side effects in most people. You'll need to keep-up on the fluids and Tylenol (acetaminophen) and watch for worsening symptoms or change in behavior. If that happens, taken him (?her) back to the doctor.