Didn't know why I couldn't emerge help2man until I Google'd the issue. Had to manually emerge Locale-gettext before I could emerge help2man. Not a serious issue but one that might be easily fixed if there's time.
It depends on elibc_glibc? ( nls? ( dev-perl/Locale-gettext ) ) So either there is really something wrong ( please add emerge --info and useflags of help2man ) or you just forgot to run `perl-cleaner --all` after upgrading perl.
Ah yes, after updating perl and running perl-cleaner --all I did an emerge --update --deep world and it automatically re-updated perl.