Quoting eKnuckles:" Continue to put lanolin and it will clear up. Ive read some mamas have put neosporin on, but had to ... [snip!] ... one boob is the super boob (just in case that happens to you and you think it's because she wasn't eating on that side)."
This is true too, my right made waaaay more than my left and was like twice the size, and I alternated feedings, so it wasn't a demand issue.
If your left supply drops you can always work 2x as hard and it will eventually get back up to normal, too.