小じわ also means fine wrinkles, but ちりめんじわ emphasizes a texture similar to crepe fabric, often implying a delicate, crinkled pattern.
Etymology
Compound of 縮緬 (chirimen, 'crepe fabric') and 皺 (shiwa, 'wrinkles'), with rendaku voicing shiwa → jiwa. The word likens fine wrinkles to the crinkled texture of crepe.