What is the prognosis of liquid nitrogen treatment for wart removal?

[MFZH24]

I had liquid nitrogen cryotherapy performed on the plantar surface on my foot to remove warts.  Within an hour of the procedure a large blood blister formed (circular, 3 inch diameter, protruded 1/2 inch).  The pressure and pain grew, and I went into the clinic the next day because of the pain.  They made a small incision, but the pain and pressure was only slightly relieved. I waited 6 more days and the blister only grew.  When I returned to the clinic, they sent me to a surgeon.  He ended up cutting off the outer layer of skin.  Now there is shallow 3 inch diameter blister with a quarter sized black and red raised area at the center.  I am instructed not to walk on it for 3 weeks and the best case scenario would be that I can walk in 3 weeks.  I am wondering, is this a common side effect of wart removal or did something go wrong during the application (the doctor mistakenly used too much liquid nitrogen)? How common is this side effect? Are deeper tissues injured (like plantar fascia or plantar nerves)?  What is the worst case scenario?  Will there be any residual effects? Thank you!