I suggest that you go to see your primary care doctor
who will be able to help you figure out what is going on.
One possibility is that you have a skin infection with a fungus known as tinea versicolor. This fungus is known as the 'sun fungus' because it causes whitish patches on the skin that are more prominent when people have been outside in the sun, mostly because the unaffected areas of skin tan while the areas with the fungus remain white. If you have tinea versicolor, there are multiple medications, most of them topical lotions or creams, that can be used to clear up the infection, and your doctor will be able to make a recommendation.
Another possibility, especially if you were sunburned this summer, is that these are areas of residual skin damage. After a sunburn or any other skin injury
, the affected areas of skin often appear paler than the surrounding skin. This is caused post inflammatory hypopigmentation. Post inflammatory hypopigmentation doesn't require any treatment, and it tends to get better slowly over weeks to months.
Start by seeing your primary care doctor or a dermatologist
in order to get a diagnosis and decide whether treatment is needed.