I would echo what other moms have said in seeing a dermatologist. However, both my son and I have had warts (he is now 5 and has gotten them twice). In both our cases, nothing worked--except time. I had mine frozen off, burned off, and medicated, and they always came back. My son's started on his thumb, spread to other fingers, then to his face (nose and right beside his mouth). His pediatrician said it was viral and that it spread because he would touch his hand with a wart to his face. For both of us, the warts just stayed in one place for a long time (a year or more). Then they would suddenly start getting bigger and spreading to nearby areas. In a few weeks time they would just die and fall off for no apparent reason. I had several doctors tell me different things to try (put a penny in your pocket and rub it throughout the day, try duct tape, try over the counter meds, etc.) but in the end none of them worked. If you are worried about scarring or how painful treatments might be, try just leaving it and being patient. I'm told the virus can last up to 7 years in the body . . . But ours died much sooner than that.
Best of luck.