It sounds as though you have a milk bleb ? a white stop on the nipple. These can be caused by a plugged duct, thrush or skin blocking the milk duct and may oocur after a trauma to the nipple.
If the bleb doesn?t hurt, nothing needs to be done. If it is painful, try to apply wet heat either with a warm compress or by soaking the nipple in warm water. Another approach is to wear a cotton ball soaked in olive oil in your bra to soften the skin and then attempt to peel away the thickened layer of skin. After the feed attempt to express from the nipple the remaining material by compressing the nipple behind the plug. Sometimes it is possible to express a thickened string of milk, which will help open the duct and keep it open.
If the above treatment doesn?t bring quick relief, I?d suggest going o see your doctor or a nurse to open the blister. It is easy to get infection when you do this yourself as there is a correct technique to opening a blister. If you do have to open the blister use a little lansinoh cream afterwards as this will speed the healing and reduce the scar tissue.
Hope you feel well again soon,
SARAH