My 4 months daughter had vaccines today. her temp is at 38.7c. i gave her tylenol, (acetaminophen) but the temp never went under 37.7. what should i do to lower it?

This degree of: fever is not uncommon after the 4 month infant vaccines. It is not dangerous for her either, just uncomfortable. As long as she is drinking/eating well and not acting ill, I would not worry. If she seems uncomfortable and the Tylenol (acetaminophen) is not helping at all (it seems that it is helping), you can change to infant Motrin.

Let it be: Low grade temperature elevations represent the increased metabolic activity of the child. I does no harm to let it alone at that level.She is too young for ibuprofen (effects the kidneys). Just make sure she remains hydrated and this will pass.