Sis, that blackening at the tip is actually super normal, it's just your areola darkening, which happens to almost lahat ng pregnant moms kaya don't worry! The cracks though, ouch, I remember that from my pregnancy and it was definitely uncomfortable lalo na once baby arrives and you start breastfeeding. Best to mention it sa OB mo next checkup para ma-check properly, pero in the meantime, keep them clean and moisturized, I swear by Mama's Choice Nipple Cream kasi it's pregnancy-safe and actually works, plus it's breastfeeding-safe din so pwede mo pa ring gamitin later. Hanggang sa makita mo ng doctor, try to avoid tight bras and irritants, and stay hydrated! You've got this, mama!