Inner Thigh Indentations Lines On My Inner Thigh?

Lines on my inner thigh? - inner thigh indentations

I have purple / blue lines on my inner thigh veins (I do not know), then as a kind of scores are. I'm too young (12) in the veins can not be and are not like the veins. Can anyone tell me what is it? (My mother told me that she tight jeans that I have to bear all the time, is that true?)

thanx

Sashi ♥