Hi, I Have Done 3 Sessions Of A Cryosauna Therapy.

hi, i have done 3 sessions of a cryosauna therapy. It gets to about negative 200 something degrees farenheight due yo nitrogen gas. After about the second session stated to get pain in my lower right leg/ankle. It bands around half of my ankle and is red, swollen, tender to touch, and burns very bad. What could be the cause so I can avoid it later on. Also is there anything I can do to treat it or relieve some of the pain?