It’s Indonesian. “Anak kecil” means “little child, kid, munchkin.” It was “polos” that was tricky. I did some ad-hoc corpus lexicography, and I think the sentence means, “The munchkin’s naive.” (“Polos” means “smooth” or “childlike,” but the connotations can vary from one language to another.)
About the alcohol swab–it’s not to disinfect the area but to make the vein stand out for easier injection.