You are not supposed to do that because the toxins might get into your bloodstream and begin to circulate systemically.
If you have not been cleansing systemically, it is very important to do this in order to correct the systemic environment that allowed the problem to occur.
This is the cure zone cleansing protocol-
I used black salve to remove some itching warts and moles and regret it. It left huge scars, and a few months later the scars and the skin around the scars began to itch. That is when I began to cleanse my system and take bloodroot internally. This is what saved my life, not using bloodroot topically. If I had to do it over, I would simply take bloodroot internally and skip the horrendous eschar treatment. I do not recommend black salve. I recommend systemic cleansing.