Your doctor is right, hemangiomas usually disappear themselves by the age of 5. However, the lip is a difficult place, in terms of cosmetics, and also because the skin of the lips is very thin and problems may arise with the hemangioma bleeding (they are quite fragile).

Propanolol may be an option, but it has to be used with care as it can lower blood pressure. Otherwise, the dermatologist is a good starting-off point.