I know for sure that that advice about your sunscreen was not good!!!  You are YOUNG - only 37 - and if you have brown spots, are hispanic, on birth control and work outside, you need a double layer every single day on your face, neck and chest at the very least!!!  Ignore him/her and continue with your Zinclear.  You might even want to double layer by putting the Zinclear on in the morning and getting the tinted ColorScience powder to layer over it at lunch (this and other online sites). If you don't like those, try a product with 3% Mexoryl which won't be chalky.

 I would recommend a second opinion and here are some questions you can ask your dermatologist (be sure they are board certified - go to AAD.org).   Does he/she think your problem is more melasma or sun damage or both?  If it's melasma, would changing birth control methods be helpful (usually yes)?  Since you work outdoors, what other things can you do to protect your skin?  Would peels be more helpful for you than IPL?   Is the IPL making it worse?  Sometimes the case if it's melasma.  What other topical treatments would be helpful?  Hopefully this will get started a productive dialogue with him/her.   Good luck!  Dr. I