Dm type i, kidney failure, recent toe amputation due to ischemia. wound is not healing properly. would supplementation w vit c help? what dose?

So sorry: I'm very sorry for your unfortunate bad luck. Sadly, vitamin C will be of no value to you. Hyperbaric oxygen may help. Evaluation in a specialized wound center is helpful - sometimes there's an element of infection present that can be treated. Good wound care and debridement is important. Cilostazol helps some people. I assume you're anemic and that should be corrected if possible.