This can be a Venous Malformation, that is a bunch of veins that have formed in an improper way.
These can spontaneously disappear until the child is 2 years old.
But if they persist when she is older then you should see a doctor, preferably a Vascular Interventional Radiologist
and have an Ultrasound
done to confirm a Slow Flow Vascular Malformation
. This can then be sclerosed by injecting a sclerosing agent like Sodium Tetradecyl Suplhate.
This would be a day care procedure and your need not get too stressed about it.
Vascular Interventional Radiologist