From the Guidelines

Acetaminophen is safe to use for managing fever in a 4-month-old infant, but its effectiveness in preventing febrile seizures is limited 1.

The benefits of using acetaminophen for fever management in infants include promoting comfort and preventing dehydration 1.
However, there is no evidence that acetaminophen can stop a seizure or prevent a subsequent febrile seizure in children who have experienced a febrile seizure 1.
The risks associated with acetaminophen use in infants are generally low, but it is essential to follow the recommended dosage and administration guidelines to minimize the risk of adverse effects.
For teething-related discomfort, acetaminophen may be used to relieve pain and reduce fever, but it is crucial to consult with a healthcare professional before administering any medication to an infant.

Physical methods such as fanning, cold bathing, and tepid sponging are not recommended for managing fever in infants, as they can cause discomfort 1.
Ensuring adequate fluid intake is essential to prevent dehydration in infants with fever 1.
Paracetamol (acetaminophen) is preferred over other antipyretic drugs for managing fever in infants, due to its effectiveness and safety profile 1.

From the Research

The safety of acetaminophen (Tylenol) for managing fever in infants, particularly those as young as 4 months, has been a subject of extensive study and debate 2, 3, 4, 5, 6.
A systematic review published in 2022 found that although acetaminophen is widely believed to be safe for use in infants and children when used as directed, there is increasing evidence indicating that early life exposure to acetaminophen may cause long-term neurodevelopmental problems 2.
The same review noted that the median follow-up time in studies assessing the safety of acetaminophen in infants was only 48 hours, and none of these studies monitored neurodevelopment 2.

Acetaminophen is commonly used to manage fever and pain in children, including teething-related discomfort 3, 4, 5, 6.
A study published in 2020 compared the effectiveness of acetaminophen and ibuprofen for treating fever or pain in children younger than 2 years and found that ibuprofen resulted in reduced temperature and less pain within the first 24 hours of treatment, with equivalent safety to acetaminophen 5.
Another study published in 2002 found that there is insufficient evidence to show whether acetaminophen influences the risk of febrile convulsions, and trial evidence that acetaminophen has a superior antipyretic effect than placebo is inconclusive 6.

The American Academy of Pediatrics recommends that parents and healthcare providers consider the child's overall comfort and well-being when deciding whether to treat fever, rather than focusing solely on normalizing body temperature 3.
Pediatricians should promote patient safety by advocating for simplified formulations, dosing instructions, and dosing devices for acetaminophen and other medications 3.
Parents and caregivers should be counseled on the importance of monitoring their child's activity, observing for signs of serious illness, encouraging appropriate fluid intake, and safely storing antipyretics 3.