"Small black dots have appeared on the tip of my 4-month-old daughter's tongue, is this normal?"

The appearance of black spots on a baby's tongue is quite rare. It is recommended to monitor the situation over the next few days to see if the spots disappear on their own. This issue could have been caused by increased suction during breastfeeding. If the spots spread or persist beyond the next week, it would be advisable to consult a doctor or pediatrician for further investigation.