Hello,
Well without examination,confirmation of a diagnosis is tough but various possibilities are there for your symptoms. First is of flat warts. They are benign tumors of the epidermis and usually occur in children. Flat warts are about the size of a pinhead and usually appear on the face, but can also appear on arms, knees, or hands.
Other possibilities are of solar lentigo and solar keratosis.
I think that you should get it evaluated from a dermatologist as treatment modalities for all are different.
I hope that helps.Take care and pls do keep me posted on how you are doing and if you have any additional queries.Kind regards.