I do not know anything about amputation. Removing a birds toe or part of a toe should be considered a major operation and you should consult a veterinarian if it becomes necessary. Whether a person is experienced or inexperienced at raising poultry doing such an operation at home would cause the bird a huge amount of pain and might kill it from the pain and shock of the operation w/o anesthetic, or loss of blood. Also as the injury is to its foot instead of say the wing there is the problem of the birds mobility in the future. removing part of a foot may effectively cripple the bird making difficult for it to move and causing it to become lethargic and sickly. Some birds do fine with foot injuries, I have a large breed hen who has a crippled foot that is no longer usable and we have kept her seperate from the rest of the flock and she is still doing fine hopping around on one foot 3 yrs later, but she needs a lot of care as she has to have a very clean pen because she cannot perch and gets dirty easily from sitting down a lot and has trouble moving around. On the other hand some birds dont and I have had birds with leg injuries that I tried to save but then unfortunately just languished and died or I had to kill them as it was obvious they were only suffering. The unfortunite reality is that if the birds feet are injured that badly the most human thing may be to kill it unless you are both able to find a vet who could try to properly amputate part of the foot under anesthetic and can afford such a procedure. I am not saying that killing the bird is the only option. At this point I would wait and see what happens. Keep it in a very clean area to try to prevent infection of the feet. If going to a vet is an option try to find one now in case it becomes nessecary. As for the comb if it is a single comb bird then from what I know the frotbitten areas will eventually turn black and fall off. Just keep it clean and if it becomes infected go to showbirdbird and ask about how to bud or remove the birds comb. I have never done this so it is better to ask there.
Good luck.