Standard advice during chemo is to get attention if your temperature is over 38 - but you have done that! You have nothing to lose by using the after hours number. I had taxol and herceptin (but no perjeta) but my only febrile issues were caused by a recurrent seroma related infection and on each occasion I was kept overnight in hospital - but I have private insurance and they do that in a flash if you are covered. Your tests won't necessarily be completed until tomorrow, but your temperature may be going up so I would call if only for your own peace of mind.