I have a wart on my foot that WONT GO AWAY!?

So I've had this planters wart for as long as I can remember. I'm 15 now and I probably had it since I was 11. And before that I had a different wart. So anyways, when I first got this wart I used a whole bunch of over the counter stuff. I used acid, freezing, a combination, pummus stones, and bandaid things. Then I went to my doctor who burned it. She said it was gone but when my foo healed it was still there. I came back and she said it was almost there and to use over the counter stuff. So I used it (religiously) for months. I came back with another smaller wart. She said shed burn it off again. Instead I went to a podiatrist. By that time I got a third wart. He said it was because of my sweaty feet. Well anyways, he used acid treatments, a combination of solid and liquid acid. I would come every week, he would sc it off and put more acid. It seemed to be working great, he said I'd be done in 4 weeks. So finally he said he saw no more wart, but would put on more acid just in case. But that it would flake off eventually an I didn't need to come back. Well it flaked off (kinda) but the wart was still there. (by the way, I first came to him right before summer started) so I came back and he switched to a prescription foot deodorant thing (formalaz) that was supposed to dry out and kill my wart. He would then sc it off after two weeks and repeat. (I used the formalaz twice a day) it seemed to be working because my wart would come to a huge head (it was painful to walk). But it still didn't go away. So he finally said he thought it was all gone and that I didn't have to come back. Well it's still not gone and I plan to go to a ifferent podiatrist. What should I ask to be done? (since burning and acid didn't work for me)