Problem with breast-feeding

Hello!

I beg for little help.

My sister(26 years old) is breastfeeding mom and her baby is (6 month old). Before 4 days one of her breasts had plugged. It's not the first time that this is happened but now it's very serious.
Now her breast is red and inflamed. My sister make a hot compresses and this relieve the pain at the moment. She is little frightened because she has a lot of breast milk and don't want to give to baby some artificial milk.
The doctors of course want to do a little split to her breast but she refuses.


Some people say that mastitis like this are normal and i've read somewhere that lecithin can be helpful?

Any idea what she can do? I'm thankful for every help. Thank you