Hello, It is quite unlikely even if that man is having HIV
infection. 3-4 days old wound contacting the the fresh wound of yours and infecting you is very remote possibility. We HIV physicians and nurses are handling such cases with impetigo
in their forearms due to scratching etc and we treat HIV infected children with problems of lesions in their hands. Infection from surface contact is very very rare unless there is copious quantity if blood or body fluid exposed and the individual's viral load
is very high. So you need not worry. You will not get the infection through this way. Cheer up. Dr SM.