My 13 year old son had his warts frozen with liquid nitrogen however the skin around is badly burned. Pls help with best treatment option?

Just local care. Just wait , in couple of wks, warts are gone normal skin around will heal with minims scar, speak to your doctor and take him to follow up visit.
Warts . Liquid nitrogen often causes blisters in an attempt to destroy warts. If the blisters are painful one can pop them with a sterile needle from the side. If severe i would return to the practitioner who performed the procedure for treatment and assurance . Topical treatments are an alternative in some cases.