Why? Why treat a low grade fever? It may be helpful, it should not affect you adversely other than being aware of it, and simply recording the levels of fever and the times it occurs may help your doctor if it persists and you need a diagnosis. If you are really bothered by it you can take Aspirin or tylenol (acetaminophen) every 4-6 hours to suppress it.
Question unclear. If you are giving or going to a dinner party and have fever, it suggests that you may have a transmissible infection. Why give it to everybody else? If you have to go, Aspirin or Acetaminophen may help to bring down the fever.
Flu. Take plenty of fluids and Tylenol (acetaminophen). If you are getting behind in your fluids, be seen in the ER for IV fluids. All the best and I hope you feel better soon.