You may also want to see the remedies for sore breasts. The following information is taken from The Wise Woman Herbal for the Childbearing Year, by Susun Weed.

Continue to nurse on the breast with the blocked duct. If you stop, you can increase your discomfort and endanger your milk supply. Nurse or pump every hour but just enough to empty the breast.

Right before nursing, use any of the warm compresses on the Remedies for Sore Breasts page.

Be sure to get plenty of rest; overdoing it can lead to mastitis. The blockage should clear up within a few hours or overnight.