...
my %lookfor;
# will look like this at the end
# %lookfor = (
#    192.168.254.1 => {
#                        first => '03/13/03 16:44:56',
#                        last  => '03/13/03 16:59:30',
#                        count => 12,
#                        bytes => 1234
#                     },
#   192.168.254.2 => {
#                           ....
#                    }
# );
#

while (<FWLOG>) {
  if (/(.*?) kernel Temporarily blocking host (.*)/) {
    $lookfor{$2}{first} = $1;
  }
  elsif (/(.*?) firewalld.*? deny in eth0 (\d+) (\w+) (\d+) (\d+) ([\d\.]+) (\d+) (\d+) (\w+) (.*)/) { 
    if (exists $lookfor{$6}) {
      $lookfor{$6}{count} += 1;
      $lookfor{$6}{last} = $1;
      $lookfor{$6}{bytes} += $7; # or whichever field is bytes
      # keep track of other info of interest
    }
    # else ignore the uninteresting deny lines
  }
  # else ingore lines we don't care about at all
}

printf "%15s %6s %18s %18s %s\n", qw/ ip count first last bytes /;
foreach my $badguy (keys %lookfor) {
  printf "%15s %6d %18s %18s %d\n",
    $badguy,
    $lookfor{$badguy}{count},
    $lookfor{$badguy}{first}, $lookfor{$badguy}{last},
    $lookfor{$badguy}{bytes};
}