The centre part of my nipple becomes dry

Hi. I'm 41 yrs old. With regular menstruation. Not sexually active for the had 6 years. Have a 5 yr old child. I have this dryness in the centre of the nipple. Comes and goes on and off. It gets better if I apply coconut oil. I have started applying nipcare from yest. It looks fine after applying. But after bathing it is dry and dark. I have attached a pic for reference . It's just one small area. The other nipple is fine. Light dryness in the end alone. There's no lumps or discharge or anything out if the ordinary. Please let me know if thisis normal and if nipcare and coconut oil should suffice please. Can the wrong bra cause these things too and how can I avoid this happening. Any advice, I'll be grateful. Also I have read that the bumps in the Arreola are also normal. Pl advise. Thank you.