Thank you for getting back with the images for my better understanding.
These looks like sun spots and in medical terms called Solar lentigines.
The distribution of solar lentigines is limited to sun-exposed areas, in particular sites of greatest cumulative exposure such as the face, dorsal hands, back of forearms, and upper trunk.
Because the incidence of solar lentigines increases with age, they are most often seen in adults.
However, solar lentigines can develop in fair-skinned children who have had significant sun exposure, especially on the shoulders following severe sunburns.
Solar lentigines that are of cosmetic concern can be treated with liquid nitrogen cryotherapy, lasers that target melanin (eg, the Q-switched ruby laser), or intense pulsed light (broadband light).
I suggest you discuss these management options with your dermatologist please.
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Kind regards - Dr. Sumanth Amperayani