I saw your previous problem on the leaves of sweet potato. Is it the same field?

There might be three major reasons for this issue. First, check the underside of the leaves to see if there are any sucking insects. If there are, use a suitable pesticide. Second, it could be due to nutrient deficiency, especially potassium and phosphorus. Third, manage water use carefully—avoid both overwatering and underwatering.

Have you used any medication? From the picture, I think it's a drug burn.