stretch mark; stria
Medical term for stretch marks, especially those caused by obesity or rapid weight gain. In everyday conversation, 妊娠線 (for pregnancy-related stretch marks) or ストレッチマーク is more common.
I got stretch marks from rapid weight gain.
I consulted a dermatologist about treatment for stretch marks.
Compound of 脂肪 (しぼう, 'fat') and 線 (せん, 'line'), literally 'fat lines'. The term is a direct description of the appearance of stretch marks.