My daughter got her shots and dr gave the ok for infant Tylenol. She's 13 lbs though. Or put her in just her diaper or onsie. Cool washcloths on forehead.
Anything above 100.4°F at less than 4 months, the recommendation is to call the doctor. If it is related to shots, they may just advise Tylenol or Motrin, but if it is not, then they may need to determine the cause. But I would recommend playing it safe and calling.
Re: FEVER):
Or put her in just her diaper or onsie. Cool washcloths on forehead.