Does birthmarks grow big contained by size?

i have a sister who enjoy marks adjectives over her body,we think its birthmark but as she grows elder , her marhs slowly dispearsDoes birthmarks grow big contained by size?
Some birthmarks commonly known as hemangiomas are not really present at birth, but appear after a week or so. They may grow surrounded by size, then stop. Most usually disappear, or involute, spontaneously beside no treatment and no residual deformity. This occur by two years of age. A few continue to grow, however, cause cosmetic and other problems, especially when an eye is involved.
There has be improvement surrounded by diagnosis and treatment of these troublesome hemangiomas in times gone by decade or so. Some Children's Hospitals have specialty clinics to treat them.
okay it depends on your molcule some will grow with you when you grow and some will stay average