I have many marks on my back. What is this?

If it's not an imprint, it may be a fat line or a growth line.

The difference between obesity model and growth line;

Obesity line and growth line are formed for the same reason, but they have different names because of different periods. If puberty grows too fast, it is called growth line. Fat lines are formed when the body gets fat.

It is all due to the increase of skin tension, which leads to the rupture of subcutaneous elastic fibers, the forced strain of subcutaneous tissue and the formation of reddish stripes on the body surface. In the early stage, it showed red or purple wavy stripes, which were parallel to each other and had no conscious symptoms; Gradually become lavender or normal skin color, soft and smooth with fine wrinkles.

You'd better go to the hospital for a checkup.