So, from what I am reading, it sounds like you are doing exactly the right things here - keeping it cleaned, wrapped and occasionally soaked. If the infection is still inside the foot, the body will likely push it to the surface and it can be treated then. The alternative is that the infection was already pushed out (thus the scab) and you are just dealing with residual swelling.
To the route of opening up the infection with surgery, that seems to be a bad call at this time especially if she isn't limping. That would cause pain and potentially introduce another infection, making the situation worse.
From this point, I would continue as you are and see if the situation changes.
Additionally, it may be worth reviewing the living space of this hen for the cause of this. If they are commonly jumping down from a high roostbar or potentially came into contact with the pointy end of a screw (or even just wood that is splintering), you may see more cases like this in the future. Making the appropriate changes now could help with preventing cases in the future.
