My son got one on his elbow area of the arm, mainly through working in apartments and other building which are continusly rotating occupants.
He tried the OTC wart removal and it went wild when he did, he then went to the local dermatologist to have it removed.
I was shocked at how deep and large and area they cut out of his arm to remove it, when we used to just get the laser to take it out.

It has formed into scar tissue and thickened in the scaring of it.
I would not recomend ever going back to one of them again.
I would go to our local vet before going back to one them, he could do a much better job than they can.

He got one on his finger after that and he sufficated it out by home methods to save possibly having a finger scarred and thickened like that near a joint in it.

Thing like doctors we so much better back in the 70's and 80's, today they are not like they used to be.