Hi. Greetings. The patches on the face may have persisted since the pigmentation may have been at a deeper level. However it's better you see dermatologist and confirm that your pigmentation is due to sunburn and not something else. You'll need to use sunscreens promptly. Also chemical peels and probably even lasers may be required to improve the pigmentation. You could come for a consultation to me or see a dermatologist near you to discuss the same. Let me know if u need any further assistance in this regard. Dr Govind S Mittal. Bangalore