How do I get rid of this dark sun patch on my neck and face? (Photo)

Hyperpigmentation of any kind needs a combination approach of peels like Cosmelan; lasers like Clear + Brilliant, Aerolase or Laser Genesis; radiofrequency like Venus Viva; and constant skin care and sun protection. Bimonthly facials with SilkPeel DermalInfusion are essential to hydrate, exfoliate and infuse vitamins and antioxidants into the skin. If you have acne you can do additional treatments and peels to get more improvement. Hypopigmentation will need more of an evaluation and possibly additional lasers to get improvement. I suggest a formal consultation with an expert in lasers and peels. Best, Dr. Emer.

First of all, you should get checked by your primary care doctor to check for insulin resistance/diabetes because that can cause dark patches on the neck. If it is truly from sun exposure, the best first step is prevention with hats, scarves, and sunblock. Next, you can use a skin lightening cream with hydroquinone to suppresses melanocytes and also retin-A cream to repair sun related damage. 
Lastly, you can try IPL (intense pulse light) laser which helps target the melanin in skin and gets rid of sun spots. You need 3-4 treatments, one month apart. Best of luck

Hello, we find that the best way to treat hyperpigmentation is through a combination of treatments in office and a skin care routine at home.  In office we use the picoway laser, chemical peels, and microneedling with RF (vivace) to treat and at home we recommend hydroquinone (which supresses melanocytes), retinols (which speeds up cell turnover), vitamin c (a powerful antioxidant which can brighten skin and help prevent from further sun damage), and of course a good sunscreen.