Why would you want to do it that way? Why even use balloons, if they are to be displayed like labels? Your best bet is to use the Canvas, plot your points and add text objects for each point. Here is a simple example.

#!/usr/bin/perl
use Tk;
use strict;
my $w=20;
my $x=0;
my $y=0;

my %nums = (
   0 => ['black','yellow'], 
   1 => ['yellow','black'], 
   2 => ['white','green'],    
   3 => ['green','white'], 
   4 => ['grey','red'], 
   5 => ['red','grey'], 
   6 => ['blue','white'], 
   7 => ['white','blue'], 
   8 => ['orange','grey45'], 
   9 => ['grey45','orange'], 
);


my $mw=tkinit;
my $c = $mw->Canvas->pack;

for (0..9) {
 my $item=$c->createRectangle($x,$y,$x+20,$y+20,
             -fill=> ${$nums{$_}}[0],
             -tags => ['rect']
      );

my $text = $c->createText($x+10,$y+10,
           -anchor=>'center',
       -fill => ${$nums{$_}}[1],
       -text => $_,
           -tags => ['num','upper-left-corner']    
      );
      
      $x+=20;
}

$mw->Button(
    -text    => "Hide Text",
    -command => sub {
            $c->lower('num','rect');
             })->pack;

$mw->Button(
    -text    => "Show Text",
    -command => sub {
            $c->raise('num','rect');
             })->pack;
  
MainLoop;
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