Skin related. What is it? cause? cure?

1)My son is 21days old. On the 3rd day of his birth he was diagonised with mild physiological jaundice. The reading of bilurubin after 10days was 10. He advised me to expose him under direct sunlight daily from 10:30 to 11am this being rainy season. The jaundice still persists; plz tell me when will this go away. 2)On his birth he was very fair and may be due to sunlight over exposure he has completely turned dark literally black. Is this skin change temporary? Will he get back his colour again? What should i do to get back his skin tone? 3)He has developed some white pimple like elevation under his eyes and red prickly heat like pimples around his neck and forehead. Plz let me know what is it? Cause? Cure? I request the paediatricians  to answer my all questions in detail, so that i can followup directly. Thanku