Stretch marks

Indented, reddened streaks that usually appear on the skin from rapid weight gain or from weight changes.
Common causes of this symptom
Stretch marks can have causes that aren't due to underlying disease. Examples include pregnancy, weight gain in obesity, growth spurts in teenagers, medication side effects or a rapid increase in muscle size through weightlifting.

Self-treatment
Many products promise to get rid of stretch marks but fail to live up to the hype. Stretch marks fade and become less noticeable over time, but they don't disappear.