Hi. Thanks for posting your concern at HCM Acanthosis Nigricans clinically presents as Velvety textured hyperpigmented skin at neck, arm pits etc. The skin is thickened and gives a dirty neck appearance. Its is unlikely that the light brown spots that you are concerned about is acanthosis. From your description i think you could be having Freckles I would advice that you visit a dermatologist who would be able to examine your concern and tell the needful that is required to be done. For dry skin i would advice that you use a mild cleanser like cetaphil for face instead of using soap. Soaps are very drying. Cleansing should be done not more than twice daily. Vaseline is occlusive and can cause acne in some people. I ask my patients to use any good moisturizer twice daily preferably the one that is non-perfumed, hypoallergenic and non-comedogenic e.g Cetaphil moisturising cream. take care