It feels quite large - about the size of a 10p diameter and is quite deep behind my nipple. I haven't breastfed from that side in well over a year so I don't think it's anything to do with that. Around the nipple has been painful the last couple of days and I did a quick feel around then for any lumps or bumps but it was more a surface check iykwim so I'm not sure if this was there then or if it has just appeared. I am just terrified that it has been there for ages and because it is so deep I haven't noticed it until now which would have allowed it to get this big. I have had a slightly inverted nipple on that side for years but I just thought it was due to Breastfeeding trauma and didn't worry about. I am just so scared right now :( does anyone have any experience of this?