It is possible, but highly unlikely. Here's why: First of all, there was cloth in between her genitals and your bare skin. Granted, this area of cloth is small, but it still covered the main area that someone with genital warts would present their infection. You can't get warts through the cloth. Second, when someone contracts HPV warts, they are contagious during their first year of dealing with the virus (sometimes up to two years), and if they are going to the doctor to deal with the warts, they may not be contagious at all moments during that first year. After your body has suppressed the activity of the virus, people are usually not contagious anymore. It is possible to contract other strains of HPV warts which would mean a person would have to go through the process all over again, but for your experience, you'd have to have encountered this woman during that year of viral activity. Given the low chance of that, and that she covers herself with her clients, I'd cease to worry about having contracted genital warts. If you find you're still worrying, just check your genitals once a week for the next three or four months, and then truly forget about it. There is no need to check more than that. Cheers.