
Applying hot (as hot as won't burn you when you put it on your inner arm) flannels as compresses, alternating with cold ones will get the milk flowing.
If it is infected (mastitis) it will vary in colour from Red, through to mushroom soup as it improves, until it finally looks normal.
Until it is normal coloured pups will not drink from that gland.
A vet (experienced in milking goats and mastitis) showed me how to do this when my Jozi had Mastitis (the emergency vet had given AB's and pain injection the day before).
What we got out was Tomato soup at first, so she had Noraclav for two weeks.
It came up literally over a couple of hours, so don't feel you have neglected to notice. Typical it was boxing day, so cost a bomb at the emergency vet.