Hi - I Had A Mole Removed By Freezing On

Hi - I had a mole removed by freezing on my front shin; it is taking over 4 weeks to fully heal and in the course has become itchy. now there is a rash associated with the site that extends 4 inches or so out and the whole front shin is itchy. Is this a secondary infection that would require medical attention? Do you have any home care suggestions.