After I moved to a new apartment, I did not realize the problem with cockroaches. I do not know if they bite or other bugs come along with them. And I was getting bites and sores until I realized from where the problem was coming from. so i bought chlorine  but that worked only partially. Then I found this Israeli invention of a kind of paste that you leave on the floor and the bugs eat it and disappear, That works wonders. but the bites and sores remained. I found out there are bugs that burrow under the skin. So doctors might give different things to take care of skin disease. But this was not a disease. It is bugs that burrow.  I found alcohol, olive oil, peroxide, iodine and stuff they call חומצת מלח salty acid to help. But only after squeezing the infected area. For these bugs leave a protective covering that no ointment can penetrate until the liquid covering is squeezed out.