I did not realize that along with cockroaches come other wormlike creatures that dig into the skin. They borrow in and emit a protective coating so that even if one puts on some sort of ointment, they are protected. I did not even know they was a problem when I moved into the apartment here. But at some point I saw some around and so discovered their nest. Then cleaned up, and sealed the holes they were getting in through. Bur what takes care of the problem with the worms after they have already dug in? The thing I discovered is doctors are not aware of these kinds of parasites They  will proscribe some ointment for some skin disease which has nothing to do with the actual parasite.  what I have discovered is the first thing is to squeeze the protective coating. Then apply alcohol, iodine, and a very diluted mixture of hydrochloric acid.   Also Peroxide.