Welcome to HealthcareMagic. To prevent sun burns, avoid going out in the peak sun hours i.e. from 10 am to 4 pm and wear long sleeved cotton clothes or take an umbrella. Also apply a good sunscreen with minimum spf 30 atleast half an hour before going out in the sun.
For the hyperpigmented skin, apply creams containing Kojic acid
or Aelaic acid are useful. Other treatment options which you can get done are chemical and glycolic acid
can also be done, but this might require several sessions. Skin resurfacing using lasers is also an option. Please consult a good dermatologist
and discuss about them with him.
Hope it helps. Regards.