infant Tylenol dose

So my poor darling girl has her first cold! She is 4.5 months old and weighs 16 pounds. She was taken to our pediatrician on Wednesday, who said there was nothing to do but monitor symptoms and signs of a high fever. She was miserable and spiked a fever of 101.1 last night so we ended up taking her to the ER at 1 am. She was given Tylenol, and the doctor said we can continue to use if fever persists and she seems miserable at our discretion. In my sleep deprivation I forgot to ask the dosage! I bought infant acetaminophen liquid. My daughter is technically under the age and weight limit on the box, googling tells me to give her a 2.5mL dose based on weight. Any advice/experience appreciated! I will follow up with my pediatrician of course, kind of just curious about moms experiences.