I'm sorry but I don't know for sure! I've noticed a white growth on my EE's comb, but she is healthy and unbothered by it. Could it be something else? Check out her crop draining, abdomen, and everything else. If everything but the comb is normal, I think your best bet is to do a home surgery on her comb.
Do NOT count on my suggestions as the best! I'm not a vet or anything. But if you think you can safely and successfully do it, cut out the lump on her comb, stop the bleeding, put BluKote or similar product on it, and isolate her to monitor progress. If nobody else replies and she steadily quickly declines, the surgery may be your best bet.
Good luck!