Eh, bintik hitam kat telinga bisa jadi bermacam-macam, moles, freckles, atau even darkening dari sun exposure, tapi sebaiknya you show it to your pediatrician just to be sure, especially since it's spreading to both ears now. I'd rather err on the safe side je, kan, especially dengan kids, better to get it checked so you can relax. Mana tahu ada kena hereditary atau apa, best to rule things out dengan doctor.