My daughter has what they call a stawberry birth mark right on her waistline. there is a strange lump forming right under it. please help?

Needs exam: Your description of the change if concerning. It would be best to have a DR or dermatologist do an exam.

Common: These blood vessel birth marks often have a connection to similar blood vessels deeper in the skin that tend to increase in thickness from birth to about 9-10 months before stabilizing. It is not an indication of a dreaded tumor.Discuss it with your doc at the next well baby exam.If it frightens you, have it checked sooner, but what you describe is common.We usually just ignore it.