Sun pimples can appear as small, red bumps on the skin, typically resembling acne or heat rash. They can be itchy or uncomfortable and are often caused by sweat, dirt, or oil clogging the pores on sun-exposed areas of the body. It’s important to differentiate sun pimples from other skin conditions such as sunburn or allergic reactions. Using sunscreen, keeping the skin clean, and wearing breathable clothing can help prevent sun pimples.