A 28-year-old woman is seen in a sexual health clinic for management of vulvar warts. She states the warts have gradually increased in size during the past 2 months. She prefers to have this treated in the clinic. Physical examination shows multiple vulvar warts without any atypical features. The clinician applies a trichloroacetic acid (TCA) 90% solution to the affected area. Ten minutes later, she complained of a severe burning pain in the vulvar region.