Yes, I think she is dealing with canker, a protozoan infection common in pigeons. You can try to remove any cankers that you can see inside the beak if they are blocking her breathing. They can extend into the throat, esophagus, and invade the crop wall. It might be too late to save her, but you can start treatment and try. If she seems to be suffering at any time, putting her down might be an option. I just finished looking for the Aqua Zole or metronidazole online, and no one seems to have it now without a vet prescription. I usually see it at Allivet, chewy, and other places, but it is not available without a prescription. You could try getting it from your vet.
@casportpony may know another way.