the craters are supposedly normal. my dermatologist said to keep on using them a little while longer after the craters appear. i had concerns about the surrounding skin as well, but it healed very quickly and did no harm. my dermatologist also calmed me on this issue. i actually had to switch from over-the-counter wart remover to regular doctor visits (freezing does not work, I did it for over a year) I then switched to the fluid acid (17%) at the dermatologist office, which left craters and burned the skin around the warts (the warts are hurting because the acid is attacking the harder skin, that is a sign of healing). Unfortunately, my warts were so bad, i went to a foot doctor who prescribed the same acid to me but in band aid form(just like Dr. Scholl's) but was 40% strong. No craters, no surrounding skin was damaged and within a month, all my warts disappeared that two years of treatment, every over-the-counter product, and a dermatologist could not fix. if your warts persist, do the same I did, go to the pediatrist and ask for the band aid form, 40%. If you stop your treatment prematurely, the craters will heal very quickly and the warts will come back with a venegence.