Open blister on your feet and digging ingrowing toe nails is sufficient to set the infection, which travels to inguinal lymph nodes, which are our first protective barrier for any infection to go beyond the territory of leg and become systemic. Once the infection and inflammation occur in lymph node (termed as lymphadenitis) cold shakes and fever occur which is again a response to the infection by our fighter cells, lymphocytes (which are abundant in lymph nodes) and neutrophils.
Previous surgery, which makes lot of scar tissue (which has precarious blood supply) and tying of an artery (again can make an ischemic or low blood supply zone, thus lowered power of infection control ) predisposes for the recurrent infection flare up.
Taking very good foot care and getting the treatment for ingrowing toe nail will help in preventing the relapses.
Please feel free for your follow up questions.