It is completely normal for babies to experience a mild fever or soreness after vaccinations; it shows their immune system is building protection. To help her feel better, you can give her paracetamol (acetaminophen). If she is over six months old, ibuprofen is also an option. Always consult your pediatrician first for the correct dosage, which must be based on her weight rather than her age. You can also dress her in light clothing, offer extra breast milk or formula, and apply a cool, damp cloth to the injection site. If the fever persists beyond 48 hours, contact her doctor.