You might be experiencing hyperpigmentation, where skin appears darker due to various factors like sun exposure, hormonal changes, or inflammation. Even with sunscreen, some individuals may still notice darkening. It's important to assess your skincare routine and consider factors such as the type of sunscreen and its application. Ensure you're applying it liberally and reapplying regularly, especially during prolonged outdoor activities. For persistent or concerning changes, I recommend consulting a dermatologist. They can provide personalized advice and treatment options to help your skin recover and restore its natural tone.