If your baby has a fever of 38 degrees, it is generally safe to give them Tylenol, even if they have already received antibiotics. It is important to prioritize your baby's comfort and well-being. Tylenol can help reduce fever and provide relief. Additionally, ibuprofen may be a good option for its anti-inflammatory properties, especially before bedtime as it has a longer-lasting effect. It is always best to consult with a healthcare professional for specific advice.