I've dealt with quite a few toe injuries in my rescue chicken & duck escapades and I find that they are always fixable! I usually find that if the area looks thickened or dark that there is pus- sometimes very hard kernel like pus- under there. This is going to sound a little cruel-- and they don't like it at all-- but I usually either do a teeny tiny lance, insert a needle into the area, or pull any scabbing off if there is any. Sometimes gooey runny pus comes out and sometimes you end up finding a pocket under the skin containing the hard kernel like pus. Make sure you disinfect the whole area and your tools first ( I use betadine).
After I get the infected area opened up I always soak their feet in warm epsom salts water for at least 15 minutes. Some will find that it feels good and just stand there on their own, others you have to hold them. Then I dry it really well and apply blu-kote (if they are going back outdoors) or sometimes just bacitracin if they are staying inside with me. It's good to the do the soak twice a day.
Unfortunately sometimes the area scabs over while there is still infection present and you have to reopen the area daily to drain and soak it. It takes persistence.
I've also noticed with all of mine that have had bad toe infections that even after it heals the toe tends to look a little different, sometimes thickened or knobby. Hope this helps!